As the title states, I noticed stores have stopped selling 30/70/100 and 50/100/150 watt incandescent 3 way bulbs, and instead started to stock 100/150/250 or in some stores also 70/170/240 W bulbs instead.

It seems even less energy efficient, and even though the sockets are rated for 250 W, many lamps have labels stating not to use over 150 W bulbs in them.

Is this to get around lamp bans?

Many of those regulations have exemptions targeting special purpose lamps where the replacement is really problematic. Although I do not know the details, this indeed seems to me as a loophole found by abusing some of those exemptions.

We may not like these regulations so it may seem as a "clever idea to f....ff bureaucrats", what it achieves is those exemptions to be revoked, causing problems where there is really no suitable alternative, really way more severe problem than "I don't like LEDs"...

Interesting, and very true.

Now, we are getting the 3 way LED bulbs, typically I’ve seen in 30/70/100 W or 50/100/150 W classic wattage equivalent from GE and Ecosmart (Home Depot brand), and also some odder equivalent from Great Value (Walmart brand) as 40/60/100 W equivalent. In a few different color temperatures as well for each.

Strangely, while the 250 W incandescent 3 ways have now replaced the other wattages for incandescent in the medium/standard based sockets, the 100/200/300 W incandescent mogul based 3 way seems less available and possibly banned?

So odd to see one bypassing regulations, but the mogul is not. Yet Amazon still sell it for now, so possibly it does bypass regulations, but if out of production, I don’t know.

There should be more manufacturers making a mogul based LED equivalent but so far, I only see it from Satco brand, and on Amazon a strange brand called “GEPLAD” which from reviews, did not fit properly in floor lamp diffuser bowl. However “GEPLAD” now offering a longer necked version that may fit to correct the issue.

All the mogul based LED 3 way are odd looking.
Would like to see more traditional shaped snow cone or even glass filament version to come from other manufactures like GE or Sylvania or Philips but so far nothing in the mogul version I can find.

From what I'm aware, incandescent lamps with a mogul base are considered "speciality" and exempt from the stupid ban.  The 100-200-300 incandescent is still available and is part of the ban because, a) this particular lamp was only available with a mogul base, and b) it is typically rated at 3900 lumens on the 300 watt setting.  Incandescent lamps over 3300 lumens are considered "speciality".   

That being said, very few brick and mortar stores carry the 100-200-300W lamp because this size was used almost exclusively in very old torcheire lamps, usually from before 1970, and most folks have since ditched these in the late 1980s/early 90s when the halogen torcheire with a full range dimmer became very popular. Not to mention energy costs have soared in recent decades, and it became clear that constant use of such a high wattage lamp wasn't exactly friendly to the average Joe's wallet.