Yes it could be done and made cheaply... if it's something that consumers actually want, beyond a gimmicky "My phone has it" selling point.
Maybe i'm just not consumer enough, but i don't really want my photos or video to be 3D, in the same way that film looks better at 24FPS and games look better at >60FPS.
I think high frame rates and depth perception are along the same lines as far as application goes, they bring ultra realism. For things like games, simulations etc that's great. But for many forms of media it seems that lack of realism and it's artistic capacity are somehow entwined, adding ultra realism seems to destroy that. Granted - selfies are tenuously artistic so perhaps this will make it into phones.