All it would take is for the cost of that 'bunker fuel' they use for shipping things to the USA to rise 1.5x-2.0x and suddenly they're no longer competitive! Then they have to start making quality products to compete like Japan does..
Then we can have our crappy manufacturing jobs back and white people will have to do actual work...
Basically we'll go back a few decades to where China looks like India again; pretty stinkin' broke.
On the downside, i think we'll start getting quite a lot more polluted.. because they do all our dirty work.
I guess there are a lot of scenarios that could play out, but i think China's boom can only last so long.