It not a gimmick. 3D has been around in one form or another since the 50’s.
But it never really stuck. I don’t think I’ve talked to anyone that actually enjoys watching movies like that.
Well it comes in waves like any money making fad. It came back in the 80s, it came in 2009, now people have lost interest. I prefer 2D IMAX style experiences which don’t distract from the film and don’t have lenses that darken what you are seeing. As for the home release market I can’t see it taking off in a big way.