The top Chinese talents (e.g. Kaming He, Fei Fei Li etc) all chose to move to the US. AFAIK, there are no Chinese institutions that employ elite foreign AI researchers. The US universities and companies still lead with a large margin in terms of high impact publications in NIPS, ICML, CVPR etc.
3 of the top 10 (all in the top 5 even) are Chinese in origin. This is a list of publications at the top venues in AI / ML for the past two years. If you extend it to past 5 years, you get a slightly better picture, but that doesn't change the 3 in top 5 comment either.
Take a look at recent major advances in deep learning: information bottle neck, mask-rcnn, transformer, normalizing flow, all originated from US/Canadian/EU institutions. Chinese academia has very serious systematic issues that discourages innovation and encourages quantity over quality.
In addition, I think the sheer number of students and resources at their disposal will ensure China have a continuous pool of talent to draw from. The US has become increasingly hostile and competitive for ML researchers in terms of academic pressure, and returning to China has been incentivized for a while now.
Can you elaborate on that?