anyone thought the above technologies could just merely be a transitional technology for lighting between the candle and the light emitting diode? i really do not think there will ever be another form of new lighting technology that runs on electricity, leds could be with us forever until maybe some unknown radical tech that does not even use electricity or whatever...

Well, any light source would have to use some sort of energy, it would never be a perpetual motion.

And the electricity became in the last century and half the most convenient form of power transfer, so all lighting sources from that era were using it. It become so convenient to control, than all automation and communication worldwide is based on it - all the computers, communication switches, etc are using electrical based signals to do their task, even when principally the same digital math could be done on any medium capable to represent the "ones" and "zeros" of the digital world.

And if the LED's would conquer the light source business? Well, it is the only device converting directly the most convenient power transfer medium we are using today (the electricity) to the light, so I would agree they would take the hold, until either we find some even more convenient medium to transfer the energy, or someone invent some other method of directly converting the electricity into the light.

And seeing the incandescents, fluorescents and HID's as transitional only? Well, then I'm convinced the LED's would be in the same way transitional as well, as sooner or later one of the options I put above would take place...

This is awesome topic and I agree!  With both you guy's ideas.  If LED's eventually are 100% "likeable" and able to light all physical areas the same as linear fluorescents, dim to an orange romantic glow for mood lighting, and provide light for fishing boats like the megawatt HID's and outlast them....I'm fearing they're here to stay and its probably a good thing for energy usage to lighten up the grid load and help the environment, etc.  But I personally would much prefer the complicated intricate processes of hot incandescent metals, arcing gasses, vaporizing elements, noble gasses, phosphors, tube blackening, EOL behavior, power drawing humming "organic" magnetic ballasts and all the other wholesome stuff of this "transitional technology". All I can say is I am glad us LG members are alive through the "transitional" phase! :-). It may be quite boring in the future....live running mercury vapors and fluorescents and incandescents may only be witnessed in collections and read about by schoolchildren lol :-(

What is transitional and what is not is not that easy to determine.

For example the Welsbach gas mantle was invented around 1880 to compete electric lighting: gas lighting used a flame as vegetable and animal oils did for millennia, then electricity showed people that lighting could be brighter and whiter. The Welsbach gas mantle is a kind of transitional technology between an open flame and an enclosed electric bulb -- however it is still very efficient and in use in campsites and chalets, in gas lamps, Coleman and Petromax lanterns, etc.

Twisted wicks burning vegetable oils or animal fats in oil lamps or candles was the only artificial light known until 1780. Who could imagine something else?
Then came the efficient Argand lamp, then gas batswing burners and Carcel or sinumbra oil lamps, then mineral oils, etc.
So: today we know LED as the future, but will it be a modern technology in 20, 50 or 100 years? who knows?

Automotive HID headlights seem transitional to me: they are brighter than incandescent and they have a different tint, but they remain a fragile bulb with a reflector and a lens.
HID street lights are not transitional IMO since they have their own benefits compared to carbon arc or incandescent street lighting: they last thousands of hours and are very bright.

I've just thought of two examples that show that the question is not that simple:

- Until 1999-2000 almost all cavers used acetylene (in France, Belgium, Canada, US,...) or halogen miner's caplamps (in the UK,...). In 1999 a led lamp came in the market (based on 24 5mm leds and dimmer than acetylene/halogen caplamps) and around 2000 another guy offered a caving lamp with a compact fluorescent U-tube. This fluorescent cap lamp didn't last long while led head lamps are the standard now.
So, fluorescent in a transitional technology in the caver's point of view, while it is one of the most common lighting technique otherwise.

- The first led lamps used 5mm leds (AFAIR the white Nichias were very popular until the Luxeon I, that allowed controlled optics and higer outputs in one die, became efficient around 2003). The 5mm body was invented for signal lamps and was not intented to general or portable lighting, although it was a convenient "package" and actually able to serve as lighting optics. we still use 5mm white leds.
So: is the 5mm led a transitional shape or not? 

@Cavannus:
  The acetylene lamp was transitional technology as well, before (the acetylene were invented) there were candles,...

When incandescent bulbs and the electrical infrastructure came, it was way more efficient and become way cheaper than candles, yet still candles are sold and used still today. Indeed, they are not the mainstream illumination source, but they still have their place.

And the same would happen to each other technology.
With each technology there is big boom and huge money when it first come, then people learn it's specifics, find a good use for it, on some places replace some other technology, just to become replaced by something else later too.

When lectric light came out nobody forced it to the users or banned pyrotechnical lighting devices

and yet the mfrs have yet to make a GOOD led reading/desk lamp.way to go guys!you cant get market adoption if most of the stuff dissapoints the end user and comes right back to the returns counter.yes thats what happened with a few friends looking to replace broken lamps that were too cheap and nasty to repair.
thats why i experimented with modding the common 12v transformer powered halogens that were all the rage a few years back.
did a few of my mods and everyone around me wants one now.even to the point of bringing me lamps to see if they were suitable for modding.
i now have a waiting list.
as for the next big step forward expect drop in replacements for 2'x4' troffers made of oled sheet.that is when they are perfected.imagine having an array on a microscopic level of every wavelength led we have now?one could truely have sunlight of any time of day on demand.even automaticly controlled to mimic variations from sunrise to sunset!

I have yet to see LEDs suitable for a reading lamp (ie one that won;t cause you headaches and posible long term harm) with its shocking monochromatic blue spectrum (and this holds for all color temperatures since what veries is only the phosphor, they are still all emitting the same monochromatic blue line)

For now the color of a halophosphor fluorescent is superior to that of all LED lamps i seen, for the light from the LEDs feels like staring into a BLB mercury lamp

When lectric light came out nobody forced it to the users or banned pyrotechnical lighting devices

Cavers experienced acetylene ban about 10-15 years ago, when some caves (mostly in the US and the UK) forbade this "sooty" lighting source; then there's been a kind of peer pressure against acetylene (I was one of the first in 2001-2002 to use led for caving; all the cavers who hardly criticized my "artificial bluish" leds, now use them and criticize acetylene).
The official and peer bans 10-15 years ago helped halogen, then led caving headlamps become the standard; then this standard helped the ban become more accepted.

For now the color of a halophosphor fluorescent is superior to that of all LED lamps i seen, for the light from the LEDs feels like staring into a BLB mercury lamp

You should try finding a lamp based on the Cree XP-G 90 leds (3000K and 90+ CRI) that mimics halogen pretty well. I've only seen them on flashlights (HDS Clicky/Rotary, Armytek Predator,...) but I really love them and now see no reasons for carrying incandescent flashlights.
I use Philips LED Flame bulbs at home (2700 K and 92 CRI rated) and find them quite close to incandescent. Others such as the L-Prize etc. still look "artificial" IMO.

Acetylene in a cave makes sense to preserve the cave. I mean, nobody ever banned gas and oil lamps and candles for domestic use despite all the fire and intoxication risks associated with them

LEDs for flashlights are fine as they are, i have no problem wih useing the "blue white LEDs" in flashlights. The problem is that LEDs with the same output spectrum are used in fluorescent retrofit LED tubes, E27 LED lamps, LED floodlights and so on where they are expected to work as the light source in a room where people will be reading, looking at computer screens etc

About caving, modern acetylene burners tend to product soot because the nozzle is larger than on older burners, hence less pressure and a yellowish flame. In addition to this, some cavers don't change their burner when the nozzle is loosing its rectangle shape, so they carry a very sooty flame. I consider this acetylene ban is a real ban, because it would be possible to preserve caves while using acetylene (with good burners, communication against defective burners, etc.).

I agree with you about the poor light quality of most of retrofit led bulbs. It's a shame to claim "led technology" in order to make a bad & inefficient product more desirable.
For example Ikea make CRI very visible on their (Lemnis) led bulb packages and so encourage their clients to learn about light quality indexes, while most of others brands (e.g. Philips) make CRI very hard to find and many others (Cree,...) don't provide this piece of information (I know the CRI doesn't say everything about light quality, but 70 vs. 92 written on the box change my expectations about the product).

Well, many makers do not state their CRI, as they use the easiest way to boost the lumen output - radiate less power in bands not contributing as much on the lumen output. It is nothing bad on this (where you really need high quality light? In living spaces of course, but where else?), but their marketing department choose to hide the parameter, instead of providing the good guide on where how to judge the necessity for high CRI....

A few "reputable" led manufacturers mention both Ra and R9 CRI values in their specs, considering that most leds tend to fail in producing a vibrant red colour.
For example LEDNovation offers some led bulbs with a 93 Ra and a 63 R9, and other models with a 90 Ra and 90 R9 CRI rates -- so that expert users can choose the best bulb according to the application.

Anyway, all these marketing battles make me think that the led we know today is a transitional technology. In a technical point of view, the blue die with a yellow phosphor has several cons although it works well. In a marketing point of view, I believe that leds still search for their "philosophy": they're intending to mimic fluorescent, HID as well as incandescent. I hope they'll tend to light quality in both "warm" and "daylight" ranges (I only know one flashlight or headlamp that offered a good CRI in 6000K, which is the Zebralight H502d that customers didn't like that much); I also hope cheap flickering drivers will be abandoned.

The real cheap series capacitor based ballasts would be abandoned, but mainly due to the efficiency reason.
The 100/120Hz flickering drivers would not be abandoned as soon, as that is the result of a driver capable of high efficiency, high power factor and no electrolytic capacitors. And the last aspect is, what enable even not as expensive design to reach really long life, while still remain quite compact. And the last two aspects mean quite a large advantage, except when the stroboscopic effect is a problem.

Regarding the blue chip plus phosphor: Up top present knowledge it is still the most efficient concept achievable. This may change, once someone come to the market with a really efficient green LED die (today even with the phosphor having ~60% energy conversion efficiency it is still the most efficient way to get the green component).
But with direct chips in the complete spectrum you can not achieve as high color rendering, with three narrow band components (assume you have the efficient green) you can not go above CRI80 - high efficiency direct emitters would have to have narrow spectrum. So for higher CRI the phosphor will remain as an important way to generate wide band light. And it this area the "industry standard" is the blue chip, partrially radiating directly, but otherwise exciting the phosphor, the main of green, yellow and orange emitted by the phosphor and for the red part are used red chips.
The problem with such concept is the difference in thermal behavior between the red and blue: When heating up, the red loose their output really rapidly, while the blue by far not as much. And this difference, when not compensated (powering the red more when the temperature rise) would be responsible for not as stable color. And that is quite a problem for high quality illumination.
So most makers still use the phosphor concept even to (in rather inefficient way) generate all the spectrum components: It simply yield way better color stability.
But this issue could be addressed in the future, so the two color chip concept could become more standard.
But in one area the phosphor concept would most likely still remain: When you need high intensity focused beam (car headlights, flashlight,...), you have to generate all the light on one spot, so on one surface. And that could be done only using the phosphor.