Actually, we can own companies in China.
They are called WFOEs - Wholly Foreign-Owned Enterprise.
There are certain hoops one has to jump through, but this is not necessarily worse that doing things in the US. For example, I think it could be easier to form a company in China than in California.
:-/
Wikipedia's write up on this indicates that those WFOE's don't have the right to sell to Chinese. They can employee Chinese to sell products back to America though.
Wikipedia: "WFOEs are often used to produce the foreign firm's product in mainland China for later export to a foreign country. They do not automatically have the right to distribute their products in mainland China, though a recent variant (the Foreign Invested Commercial Enterprise FICE) has the ability to do so.
"WFOEs are among the most popular corporate models for non-PRC investors due to their versatility and unique advantages.