What about 3D video? If full-blown 3D video could magically appear all of a sudden with a low-cost implementation for both creators and consumers, I believe it would be a smashing success. In practice, however, the path to getting there would be more tortuous. And the relevant question is whether intermediate milestones in that direction would be rewarding enough to producers and consumers to make the investments worth it.

I think 3D video is not so technologically far off, and that the real problem of VR is that no-one has really worked out what to do with it. There are all sorts of visions of it in science fiction, but that's all fictional evidence, and actually building a VR platform that everyone will want to use is a hard problem. VR systems go back at least to the 80s, and there has been steady technological progress in that time, but the most successful VR social platform, Second Life, has never obtained a mass userbase.