I don't think 3D video was really a different class of media. 3D would never replace animation but imo real 3D would replace 3D projected on to a 2D screen just like 4K replaced FHD and FHD replaced HD.
I honestly think AR is poised to blow up, there has been a lot of sustained activity in the space for years - including lots of exploration of business/industrial uses - and we haven't even seen a true consumer device yet (Google Glass doesn't count). It's going to simplify/streamline a decent subset of the top uses for smartphones, while also providing novel experiences.
I do believe VR is here to stay, but I really think that's going to be more gamer-centric. The 'social' aspects of VR seem to be very, very niche; most of what users are talking about (and spending time/money on) is games.
All of the AR use cases seem to have been mostly replaced with the smart watch. The only thing the smartwatch is missing is having an always on camera and mixing real and fake images which seems to be not as useful as getting notifications and navigation info on your watch.
Or perhaps you expected sculpture would have supplanted painting?
3D isn't really what we want for every medium. I would argue the same is true for VR.