Us 3D fans are a very small percentage of the population. The people who did not buy a 3D TV because they didn't want to wear 3D glasses are an even smaller percentage. Glasses free TV demo's have been around for many years with none ever produced. The ones I have seen only work at sweet spots. Maybe they are better now. There is a petition with over 20,000 signatures to LG to bring back at least one model with 3D. LG is not interested - "As said, 3D has been removed but that decision was not driven by engineering concerns. It has not affected the pixel layout or brightness in any significant way. 3D is just no longer a big selling point, says LG."
I think it should be not promoted, just a feature on the TV that you can select if you want to use it.
20000 unverified signatures means probably 5000 or less actual people including many who don't have or wouldn't buy 3D and are just being supportive. My guess is that's about 2M short of being able to start a conversation. I would actually be somewhat interested in hearing the technical issues with an aftermarket modder being able to do something. I'm not at all clear where the 3D is added to the hardware.
Is the 3D inside the actual panel itself, some sort of overlay or component outside the actual panel, or is it mostly a software/circuit board issue? The first would seem to be a nonstarter for aftermarket and would even require a significant manufacturing change at LG/Sony plant, the middle would be much easier to restart manufacturing since it adds an additional step, the last seems like it would be too simple to be the case or else somebody would already have done so. Still I am a little shocked that some enterprising company wouldn't have tried do it to appeal to the hole in the market. For years there have been 3rd party Region Free modders, 3rd party multi thousand $$$ refits of audio equipment to add various things including green ink optimized laser pickups, $3000 power supplies, various additional connections which may or may not actually yield real world results.
I guess the Projector option may be so readily available (and relatively inexpensive) to limit the real market for those who demand a 3D option