Very true, 3d has always been just a fad and always fails. I remember in the 80's, 3D had a bit of a revival of the 50's tech and then went away. Avatar was the big catalyst this time around and they will probably try to bring it back in another 30 years again.
Good thing is the Entertainment, tech, TV manufacturing industries are not likely to have two duds in a row. 4K is catching on and we're in the thick of it, running with the big dogs!