I'm curious (1) how much of these people's education or experience was subsidized by the American economy and (2) how common the same situation is in China (i.e. US expats training up in China and taking that expertise back to the US).
If (1) and (2) aren't aligned, it could be one of the factors contributing to the growing sense that we pour a bunch of money into higher-ed without seeing much return.
I don't mean this from a US nationalist or political perspective - I'm merely speculating on the economics. Are the incentives for coming to the country aligned for both the person and the country? Many companies will pay for employees to go to grad-school but demand repayment if the employee isn't still with the company N years later. Would such a system for college/work visas make any sense to help keep talent?
My friends went back to China because the US is incredibly unwelcoming to hard-working immigrants and provides no reliable path to citizenship or permanent residency besides fraudulent marriage. Why should intelligent hard working people put up with that? At a certain point dignity and a reliable future are more important than the chance at a higher salary. The more developed China becomes the less reason there is to put up with those hardships.
It's hard not to overlook the fact that a lot of would be immigrants make no effort to assimilate and cluster themselves off from mainstream society; especially in a immigrant welcoming area like Silicon Valley. I bet if you were to go to China/India etc., no one's going to go out of their way to accept you.
(BTW, I'm an Indian citizen on H1B and I'm saying this, you can downvote my post but it doesn't change ground realities)
If you wish to become an American, I wish you all the best of luck (sorry for all the paperwork) and welcome you to our country with open arms.
I am not American, so correct me if I'm wrong, but isn't the melting pot metaphor about taking people from different cultures and backgrounds and "melting" them together into one much more homogenous culture?