Foreign websites are, as a rule, very badly reachable from within the country. I don't even want to use them personally, let alone build a business on them.
As an example, the rest of the world hasn't mass-adopted Baidu and isn't going to. The same has and will go for most of China's services.
Baidu is heavily shielded from external competition due to both nationalism and government controls (censorship etc). A protectionist's dream? No, a trapped nightmare, they can never compete properly with Google on a global scale. Seeing as China represents about 10-12% of global GDP, Baidu will never derive a meaningful business from perhaps 3/4 of the global economy accordingly.
Live by censorship, die by censorship.
I can access Baidu from the US... but they clearly aren't trying to get my traffic -- the site is in mandarin.
So I don't understand why you think they're trapped... if they wanted to, they're free to expand outside of China.. there are few countries that have similar censorship.