The real whole shtick is run economy in closed cycle to keep currency weak. Or the good old 1930s trade bloc economy. They're not just good at optimizing costs, they charge appropriately in CNY and inappropriately in USD. Workers don't care about obscene undervaluation in USD so long that they have bacon on the table after few hours of work.

It's not that rare that Chinese products are sold below cumulative costs of Western equivalent products and services, let alone prices. Chinese(<-substitute this with appropriate East Asian nations past and future) economy just isn't coupled well with the rest of the world that USD converted cost calculations would work. This in economic theories is sometimes explained as exports of starvation and/or overproduction, but IMO that make less sense when they've been doing it at scale of multiple decades.

The craziest example of these is Chinese PCB prototyping services: as cheap as $2 per 5 pieces with $5 extra for complete assembly and $15 shipping. $5 each would be darn cheap in the rest of the world, even $50 each for the board and $150 per assembly work would not be so absurd. There's just no competing that.