That manpower is also the cheapest as far as I know, not to mention the money trap that China puts other small countries in to create a new Silkroad. But, China beating US when it comes to economy is still a dream to be fair, the economy of China is exclusive and most of their wealth is invested in real estate bubble that does not pop because they have exclusive economy.
That is simply not true. Manpower in China used to be cheap, but that was one or two decades ago. The wages have risen to such a level that they are now 2-3 times higher than the comparable salaries in countries such as India and Indonesia. On top of that, they are now getting strict with environmental and other regulations. Lax regulations attracted a lot of investment earlier.
If you compare the salaries of US citizen with Chinese citizen then you can see huge difference in the minimum wages.Of course US doesn't have huge amount as minimum wage but still they are far like 10 or more times than average pay in those countries you mentioned. What China did is created more employment with very low pay so everyone can work which will help their government to become better in economy as well.