I don't think if 3D happened now, rather than when it did to make everyone sick of it, that it would have changed fortunes too much.
But I do think something that can set the theater experience further apart from watching at home in a similar way would be beneficial.
Alternatively, this is kind of anti-consumer, but does anyone remember how long it took for a movie to hit home video back in like, the '80s?
Maybe if movies didn't hit streaming three weeks after opening in theaters, people would be more inclined to go and check them out when they are.