The US could even have a higher skill level on average(1), and still have way fewer skilled developers. As Jesse Eisenberg asks in The Social Network, "Did you know there are more people with genius IQ’s living in China than there are people of any kind living in the United States?"(2)

(1) Your guess is as good as mine.

(2) Any relationship between IQ and developer skill is left as an exercise for the reader.

Btw I don't think the China thing is actually true unless genius means something like top 20%. I would imagine genius meaning something closer to top 1%.

Yes 20 % of China's population is roughly the population. So it's a fancy way of saying that China is five times as big as the U.S. Which it is!

The real interesting comparison lies elsewhere. Also we have to take into account that we can not use the same tests on intelligence on both populations.

"The real interesting comparison lies elsewhere. Also we have to take into account that we can not use the same tests on intelligence on both populations."

I actually think that intelligence test questions have highly correlated difficulty when given to people from different cultures (even more different than US/China). I.e. there's broad agreement in terms of what questions are hard/easy.

Could also be selection bias. Outsiders may only hear about, or encounter, the better ones.