I think something that also plays into this is the fact that 3D content producers, in their efforts to "show off" 3D capabilities, insist on breaking the 3:d wall by putting stuff into the viewers room, where they don't belong(mentally). I think this is why, to me, 3D movies look less "realistic" than 2D movies.

It would be interesting to know if the "less realistic" effect was also something experienced by viewers at the time of the shift between monochrome and color movies. And if it was overcome by technology improvement, or by viewers simply getting used to the new media.

I think the bigger issue is that most of what's presented as "3-D" in modern times is fake. Most people have seen exactly one movie that was shot and rendered in true 3-D: Avatar (well, that's two movies now).

Other than that, they may have seen a Pixar movie or Hugo in true 3-D. Or the Transformers one where they rampage through Chicago.

Otherwise, it has all been post-processed fake-3-D crap that unsurprisingly turned audiences off.

Also there's a misconception that 3-D is only good for spectacular movies. Hugo showed otherwise, and anyone who has experience taking 3-D pictures knows that the best ones are often indoor scenes of dinner tables or rooms or normal objects, or water.