The problem for product companies is that the secondary market still exists, and people's perceptions of a brand can be affected by its secondary market just as well as they can by its primary market.

If Apple isn't in China, that doesn't mean that nobody will be able to sell iPhones in China. That just means that Apple won't be selling iPhones in China. But someone, somewhere will still be importing iPhones into China, and people will buy them, and people will associate the resulting product experience with Apple. Those people will then blog about that experience, putting their perceptions on the world stage, where people in other countries' perceptions of the product can be affected by that conversation.

Which means that, if Apple has no Chinese app-store, then people in America will end up thinking worse of Apple. The American zeitgeist will be touched by Chinese-Americans who read Chinese-language blogs written by people living in China, where the experience of having an iPhone will suck because Apple "doesn't support China."