Obviously the Chinese have stolen all of the plans. How many Western experts do they need to recruit to do this all themselves?
The fear is not that the Chinese are stealing our designs, but that they are surpassing our designs. If they are just stealing, we will come up with new designs, that will not be stolen, and leave them in the dust. Besides, as the USSR learned, stolen designs are often worthless without the know-how that was developed with those designs.
Recruiting experts is a real problem for China. The flow is usually the opposite direction. How many people born in China end up working in America? How many people born in America end up working in China?
To use AI as an example, The Economist recently mentioned that 60% of AI experts live in America. Two thirds of the American resident experts were not born in America. That means, that we have 60% of the world expertise with immigration, and, at best, 20% without immigration. I say "at best", because American born AI experts would move abroad to work with colleagues, if America shutoff immigration.