The issue I see (no pun) - to watch a color film didn't require special glasses, same with the inclusion of audio.
Surround sound - I personally use it and like it - but many of my friends live in apartments, or have children sleeping - tend not to. So that's likely less of an issue with sound stage - more of an environmental one.
As for 3D - launch it without the need for glasses - and I'll show interest. I'd much rather have it with games and even with a computer UI. Pipe dream on that latter part, I know. But if you could get a decent 3D display that wasn't tough on the eyes, didn't split up frame rates, and didn't require glasses - I'd gladly move on.
The other bit is timing: Economy still in the crapper everywhere I'm looking, and people are still "upgrading" to their first HDTV - many people keep TVs until they die, no longer interface, or they finally move to a bigger place. A lot of those people don't feel like shelling out more $ just for 3D. Especially with the lack of offerings / justification in the first place.
My 25c.