The problem is that it's also not free money. The students who get their degree but can't use it have to pay the money back just the same as students who got the degree and get the high-paying entry level job.

So getting a degree is a gamble, because you either come out ahead or you get hobbled by it for the rest of your life. Whereas if you did indeed get free money to get a degree it would eliminate the hobble and produce a class of well-educated people who could afford to work for PD wages.