That's a double edged sword. Yeah, the government doesn't have the profit motive that predatory lenders do, but they also lack the incentive to say no to students who are borrowing money to study things that won't do much to help them pay it back. Politicians don't get re-elected on a platform of "let's reduce student loan amounts" or "let's give less money to students who are studying subjects that won't help them earn much". And the bureaucrats running the program don't have the power or the incentive to impose discipline here either.