Lots of wealthy people move from Europe and Japan to the US every year. And this is despite the rough parity in wages. I suspect that for a lot of these Chinese, it's a fear of future political turmoil, rather an economic slowdown. In some cases, it's corruptly obtained funds being laundered abroad - note that Bo Xilai's son was driving a Ferrari/Porsche that could not possibly have been afforded on Chinese government wages. Obscenely rich people have all kinds of reasons why they move abroad. People of moderate resources move for one main reason - the grass is greener...
One friend was of German ancestry and even though his people had been Russians since Catherine the Great Days; they were still ethnic Germans and second class citizens, couldn't ever get a good job, move up. Main reason my friend moved to Alaska. Funny thing is he still thinks Russkie Hockey is better than North American Hockey though.