I did not mean to imply ex post facto.
Let the law stand for every new loan application, and watch university financial offices change their position on accepting students that they are pretty sure will never graduate, work productively and pay back their loans.
They could start by eliminating every program that includes the word “studies” — as in women’s studies, native American studies, lgbtx studies,... None of those programs equip a graduate to do anything but teach
women’s studies, native American studies, lgbtx studies,...
Your idea is a good one. I would only add that the amount available for loan should decrease a few hundred every year (starting in 4 years) to phase out the program.