Sure humans can be exploited bit more than the Chinese, but not a great deal more and not for much more output. Don't forget that very few nations would be willing or capable enough to support what China has done.
The machines are now beginning to replace the lowest human working conditions for mass production.
Labor of Slaves, then unprotected workers, then exploited external workers:
It has always been about how much we can get away with. Now we have reached the point where soon the most desperate humans will be unable to compete against machines. It is the story of John Henry but more broad than ever before.
It need not be 100% machine-- where gamers could be unwittingly helping their parents lose their jobs by providing the tiny bit of intelligence the machine lacks their parents used to provide. Small farmers have been dying off for many reasons and no computers were required; they are an example of empowering 1 person to do the work of dozens. Robots will take that far beyond what machines alone could do... to the point where the human in the equation is only an owner and everything is artificial.
In our lifetimes there will see the 1st 100% artificially run corporation; some private owners will decide to be the 1st, it is not like most CEOs are actually that useful or don't already decide everything based upon stats (which a machine could do with a little input by survey, game, or the owner.)