Regardless of the 3D aspect, the movie theatres and Hollywood folks have seen how good digital projection can be, and ultimately, how much easier it will be for them, once the transition is made.
I wouldn't put too much faith in the demise of 3D saving film projection. It might postpone it, but they didn't have digital anything in the 50's.
3D has a future, and I personally think it lies in autostereoscopic displays that require no glasses. When this takes off... 3D will be here to stay. Just like stereo recordings completely have superceded mono, once 3D is as simple as looking, it'll become standard.
Autostereoscopy has been possible for years, but never before has it been so well poised to become a mass-marketed reality.
I also agree with Umut & Klanmeister; 3D can be used very effectively, and lends to the experience. Just because you record Michael Bolton in stereo doesn't make him any better than in mono, but listening to the Ventures live in Japan, 1965, in stereo.. that will put you in the seats of the auditorium.
The vehicle just gets a passenger somewhere, but the right passenger in the right vehicle... BOOM!