The importance of immigrant “talent” is clearly overstated. Japan became a powerhouse in the 20th century with virtually no immigration and a significantly smaller population than the US. China is becoming a technological powerhouse with no immigration as well.
I think the corporate/globalist perspective looks at the liquidity of talent as well as cost. Having a native talent pipeline is possible, but it's expensive and takes a long time to create. On top of that, it's not very flexible if an industry suddenly shifts. Re-training is a much more difficult than simply hiring a different set of immigrants. It's important (at least to corporations) because it makes a significant difference for how quickly a company/industry can adapt and evolve to stay competitive in global markets.
Even more importantly, there's just a lot of people in China. New York City's population is approximately 8.8 million; that is the scale of a mid-sized Chinese city. The population exceeds 1 billion, which is difficult to comprehend in terms of scale. The reference I like to use is: 1 million seconds is ~11 days, whereas 1 billion seconds is ~31 years.
To put it bluntly, China quite literally doesn't need (nor wants) the average software dev on HN. The immigrants they would likely want are those with expertise in much harder technical disciplines (semiconductor R&D etc.)
