3D TV's died off largely because making a 4K 3D tv was impossible at the time. For one HDMI didn't have the bandwidth for it, and second making a 4K screen that was capable of displaying 3D at 4K was not capable of being produced. Plus with the lack of content, it was clear to see why the feature was forgotten.
3D @1080p at the time was pushing the HDMI bandwidth limits, and even then for side by side content you were looking at 720p video anyways. There was more advanced ways to push 3D than side by side, but for me side by side was how 90% of my digital 3D content is stored. I still have my old 1080p dlp projector with 3D and my active shutter glasses, haven't used 3D in years. But the experience is just as good as it was in theaters.
The glasses suck, I would love to see something like the 3D effect found in the 3DS brought to TV's in the future. The Depth effect in the 3DS games that really show it off was just great. Maybe in 10 years.