This issue is fixed by making higher education free to everyone, which is what happens in Scotland. No fees to collect from fleeing emigrants. This works a treat because universities in Scotland are public institutions with the tuition fees they charge set/capped by the government (the rates they can charge the government, essentially). The country benefits from an educated workforce, especially because there are many high-tech businesses in the country that can employ them (letting the government recoup their investment in the form of income tax).
Loans for living expenses are also provided on a means-tested basis, and these are paid back by graduates only once they start to earn enough money. If they never earn enough money, they never have to pay their loan back. Also, if they haven't paid their loan back in full by the age of 50 (or something like that) then it is written off. These loans are provided by a semi-governmental organisation which has the power to collect the fees like any bank, so fleeing abroad will work only as well as it would for any kind of loan.
This probably sounds crazy to most Americans, but it works, and it receives overwhelming public support. It seems the only people complaining regularly are the universities who say they make a loss providing the education, but this argument is usually muted when you consider the huge amount of money the government spends on research in these universities (and lecturers are usually also researchers, so you can't really separate the two).