Trilux do it! The Lumega! I think Philips should do it and bring back the SGS!

Mainly because LED and HID lanterns have different requirements, an LED only needs to be able to fit a rectangular driver, terminal block, photocell and a surge protector in the gear chamber, as well as a flat LED pannel, with a heatsink on top. This is all very thin, and uses the minimum amount of material for the best performance, whereas a HID lantern body would have lots of wasted space and wouldn't get proper heatskinking while also using more materials, creating a more costly and less reliable lantern.

With that said, Philips did do an LED version of the Selenium and currently make a modified LED version of the Iridium.

Why don't they do the Selenium any more?

Presumably wasn't selling well and was costly to make. As LED technology advanced and they made newer designs, there was no reason to continue the selenium.

Thats just my guess though.

The main design goal with LED lights is to spread the light evenly on the road (that's what sells in the photos, like in the LED vs HPS pictures Max used to upload to the gallery), including in the range where it doesn't even matter anymore

Our vision is capable of handling light level differences of 1000:1, handles easily 10:1, in the HID days 4:1 was considered awesome, but now LED lighting specialists feel the need to achieve <2:1, and screw every other parameter that was compromised to get there. So not much was left besides flat lens panels with a specific lens shape

Then, the "swatter" form factor is about as optimized as it gets to be able to heatsink the LED array of this configuration, with the least amount of Aluminum possible

Any proper optic control at the light source itself, to reduce the luminance, hide the light source above the cutoff line, or provide any sensible cutoff (and not 90deg of basic FCO), got thrown out of the window

The fact that most of the people judge how good a light source is is by its glare (ie more glare - better lighting), and that aesthetic designers get hooked so easily on the "smart" aesthetic of "swatters", don't help here either

SOX lantern as is may not be the optimal in terms of efficiency and glare, especially because it eliminates the cutoff that can already be achieved with the LEDs alone. With SOX lamp the light was not interfering with vision and not causing eye strain even with a bare lamp, the same cannot work for LED without additional optical components under the diffuser