The demise of 3D wasn't surprising to me either. You pretty much gave the best reasons why. Personally, I hated the the "powered" glasses that were needed to make this all work. The passive glasses were not as good. For some reason, no matter which ones I used, I would start to get a headache after just a few minutes.
Unrelated to the 3D subject, but maybe related to the demise subject, I do not see Dolby Atmos and DTS:x catching on. It seems that there are very few movie discs with either one on them. And, I have seen absolutely no music discs or downloads with Dolby Atmos or DTS:x. Also, as an owner of an Atmos receiver, it seems very involved and troublesome trying to get it all to work. I am starting to wonder. Are these two surround formats in trouble already and perhaps headed to graveyard?