You're assuming it's about economics, but it has almost nothing to do with that. Foreign companies like Ford and GM can and do sell in China.
The reason China restricts foreign internet companies specifically, is because the government lacks control over what information is shared on such apps. China is a dictatorship where free speech is considered dangerous.
They did, largely what China did is make any companies that want to do business in China partner with a local company. From there what happened in many cases is the foreign company had their IP stolen and then shut out of the market.
China doesn't want western companies operating in China, they want western IP owned by Chinese companies operating there. That's why so many companies have pulled out of that market.
And that’s my point really. US tech companies have all kowtowed to CCP for the past two decades trying to gain access to the second largest economy.