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.

I think the world would be better on the whole if such people returned home and improved their countries. The US cannot brain drain the entire world for its own benefit.

Those foreign students usually pay for the education they receive, they might not be willing to do so (or as much) if there are strings attached. Besides, I don't think any country should aim on brain draining any other country, that kind of selfishness will be counterproductive long-term. Who knows, might be what we're seeing right now (the US self-sabotaging). Karma's a bitch.

I like the idea of incentivizing people to stay, but I don’t know how we could “require” it. I don’t want the U.S. to implement exit visas or egress control.

That seems like a pretty good idea that’s worth trying.

I think the current logic is that foreign students pay the full unsubsidized sticker price, so it’s basically a profitable transaction.