It's what sells TVs that counts and now that the new has worn off (and 3D has gained negativity in some circles), it's not what will sell TVs. Disk makers have also helped lead the decline of 3D with 3D disk prices. Also, 3D has become a standard feature on a lot of TVs. You don't hear auto manufactures touting ABS brakes anymore - same with 3D to some extent. Most manufactures are relying on the new kid in town (4K) to sell TVs. Personally, 3D has more attraction than 4K. It would make more of an impact in my viewing than 4K, but sales definitely doesn't see it that way, and the promotions go on.
Being what digital technology gave 3D in terms of quality, I don't see it going away, but it won't be a big deal either in the future of HD. Give 4K some time to "mature", and it won't be a big deal either.
After "playing" with 3D for the last couple of months, I agree that it is not a mature technology. Charging the glasses, wearing the glasses, eye strain, ghosting, etc. I have only watched one full length feature film in 3D, Tron Legacy, which does not have some of the more extreme effects. Still, at the end my eyes were too tired to watch even 2D.
Then some rather odd behavior on sports shows when telephoto lens are used. Compression of perspective is common on telephoto lens. But when a player on the side line looks about as tall as a player mid field, something is way wrong.