- science funding is controlled by the state (and thus politics) in many leading countries, especially China. Doesn't seem to hold them back
- the US pays people vastly more than other countries, and will continue to have the ability to fund expensive research more than others. Maybe it will regain the political will to do so in coming years
You're right that uncertainty is deadly to investment, and signing up for 5 years of a PhD is certainly an investment. But it's hard to see this turn into an actual brain drain, if only for lack of a better place to go.
- science funding is controlled by the state (and thus politics) in many leading countries, especially China. Doesn't seem to hold them back
- the US pays people vastly more than other countries, and will continue to have the ability to fund expensive research more than others. Maybe it will regain the political will to do so in coming years
You're right that uncertainty is deadly to investment, and signing up for 5 years of a PhD is certainly an investment. But it's hard to see this turn into an actual brain drain, if only for lack of a better place to go.