Well I guess the first step would be luring Chinese scientists currently in US back to China (many of those have US citizenship and would also be counted as US scientists)
The problem with US is for foreign nationals, there is a preset role for us to fit in, while in China, it offers more potentials. I won't say certain it is black and white question at this moment, there is trade-off in between. Living in US is no longer the non-brainer
My sample based on my circle of Chinese PhD students that have graduated in the last 5 years indicates a more willingness to go back and several have.