Regarding your last point, back when my political views were "evolving", I had thought about if, instead of handing foreigners diplomas and kicking them out of the country as fast as possible, we should do the opposite: have student visas require that the recipient stay in the US at least five years after graduation, and then fast-track them through the permanent residency -> citizenship pipeline. It made no sense to me why we'd educate someone to get a degree in chemical engineering, possibly from a rival nation, and then send them back to where they came from. We should "brain drain" other countries, not the other way around.