While that's certainly possible, it would mean a hell of a lot of work for the developers for background details that would be much, much easier to fake locally. I can't see it being practical outside of maybe an mmo with a massive number of AI routines, but that would be online anyway with calculations for the whole server and not just a single user.Really depends. Weather physics calculations would certainly be something easily pushed to the cloud. Group AI is another. Take GTA for example, the cloud could compute AI routines for all AI, the only time AI is calculated locally would be for when player interactions take place.
The hospital I work at tried to implement cloud computing and virtual machines. It was a disaster. While a neat idea, it's the sort of thing that just falls apart under real world conditions. And that's with servers on site, not several cities or even states away.