Let's turn this around - would the US win if young, skilled people were net-leaving it?
Imagine spending 25 years raising, educating, feeding, and clothing a person, investing over a million dollars of money and labour in them, and then they just pack their bags and leave.
Educated, skilled, young immigrants are a colossal gift to the host country, and a crippling debit on the welfare and prosperity of the country they have left.
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Anyone who has ever given it more than thirty seconds of thought knows that countries become wealthy when people living in them work - and make stuff. So what do you do to improve a country's prosperity?
Obviously, in backwards-logic, you start raising barriers to people who want to do useful work in it.
(Because dealing with the systemic issues that have resulted in the country becoming prosperous not being correlated with the plurality of people in it not becoming prosperous would upset wealthy people who don't actually build anything.)