They have a large domestic population of people willing (~needing) to perform work despite scant worker protections, forming continuous domestic rural-to-urban

They have a large domestic population of people willing (~needing) to perform work despite scant worker protections, forming continuous domestic rural-to-urban migration; they have plentiful extractable raw materials and aren't particularly concerned about the environment; they are able and willing to take on government debt partly because internationally their combined their military and economic might doesn't make it very likely that anyone will bother to collect. The problem is as China's acquiring a "middle-class" that begins to resemble its American counterpart in the 1950s, the pool of people in China who will do just about any job is decreasing. Middle-class people use their increased economic security to develop a sense of vested agency and are less likely to voluntarily let their living and working standards dip. Therefore, the most exploitative production is moving out of the Chinese mainstream and into the rural fringes of its own society, or elsewhere altogether.