Even though they are paid little, there is no widespread slavery anywhere. China is little different than the US was in 1900 as far as wages and working conditions. As China and India mature, their work force won't stand for those conditions for long.
As for those workers not buying stuff, they couldn't really afford a lot of it anyway. High wage demands (unions) had as much to do with the destruction of labor intensive industries as anything. Protectionism only subsidizes unions.
That's a bad thing for America and I'm glad Reagan, GHWB, and GWB felt the same way.
Cheap stuff isn't cheap.
I actually agree wholeheartedly with that, but we are in the minority.