---What I said about efficiency in China is a faithful description of what academic econ commonly says.

Moving production to the location with the highest comparative advantage is the most efficient things for a market to do, that doesn't imply that the final producer is the most efficient producer.

---Still, my explanation for why China is sewing the buttons and South Carolina is not is correct: The government in China makes their young women offers they can't refuse.

So what about all the young woman in Taiwan where this happened before China was the low-wages threat? What about South Korea before that or Japan before that? The "offer they can't refuse" is that if a young woman goes to a factory she makes twice as much as she did on the farm, but with better access to "nutrition, medical care, information systems, transportation systems, public health, public education" than she would have had on the farm. From a global welfare perspective its a lot better that three Chinese women go from desperate rural poverty to moderate (by global standards) urban poverty even if it means some woman in Carolina going from working in a textile factory to a lower paid job at Walmart.