Because "Microsoft Research" doesn't have to consider silly things like profit (or even marketability), that's for big MS to figure out.

Neither does Bing (at least so far).

You become the first company to launch a phone that can be interacted with in 3D, you become very, very profitable.

Not if your phone costs thousands of dollars to manufacture and you haven't yet worked out how to make the 3D interaction actually useful for anything.

I can't imagine how his kind of interface would ever be useful in a phone. Interface is determined by form factor. Kinect is great across a room, but for a hand held device?