I think there's a very strong "If it ain't broke, don't fix it" attitude in China, and most of the people I've met here don't consider IE 6 to be broke, so they see no reason to fix it. After all, every mainland Chinese website still supports it (circular, I know) ...

Still, new consumer machines often have Windows 7 installed, from what I've seen, so things are moving forward. I don't have any numbers though.