We have let it happen in Africa many times, buy people with mostly machetes.

Here we are talking about what is now the biggest, baddest bully in the room. 1.3 billion people, our entire economy in hostage and the nuclear bomb.

Chine doesn't have to worry about the opinion of the rest of world.

They could just turn off water and electricity and blockade naval food imports. Any independence movement would capitulate within a week (or starve within two).

Which is the reason why HK was gifted to the PRC in the first place - it cannot be defended against a siege.