> this is forgetting that the US exists.

I did not forget this. I think you overestimate what the US can and is willing to do there, and also what the incentives would be for people to escape to the US. This is not Vietnam in the 1970s, staying right there may very well be the preferred choice, even if China takes over. Especially if they make a very nice offer in advance. Should Trump win that may look even worse.