>how could the US government stop this from happening.
Lots of simple solutions if we look at other countries that restrict emigration. USSR and North Korea had models that worked pretty well. High boarder security, labor camps, family punishment, and asset seizure.
These could all keep people working and generating tax revenue in the US when they want to leave.
On a practical level, I think the idea of coercing people to stay in the USA would be unpopular, especially when contrasted with the current wealth tax on exit.
Lots of simple solutions if we look at other countries that restrict emigration. USSR and North Korea had models that worked pretty well. High boarder security, labor camps, family punishment, and asset seizure.
These could all keep people working and generating tax revenue in the US when they want to leave.
On a practical level, I think the idea of coercing people to stay in the USA would be unpopular, especially when contrasted with the current wealth tax on exit.