Even if educated people start moving to other global north countries, that’s still a problem for the US. Meanwhile, it’s also worth remembering that a lot of people in STEM are immigrants to the US from the global south. They may leave the west entirely and go back to their home countries where there is growing demand for their skills. Meanwhile, China has already largely caught up in terms of education. Chinese universities are taking top spots in global ranking, China is now producing both higher quantity and quality of research than the US, and China has far more STEM graduates. I’d argue we’ve already hit the inflection point where Chinese technological progress is outpacing the US in most areas.