It funnels poor people into low paying jobs, and those who are better off into higher paying jobs, as they can afford the risk of taking out the loans (and likely have parents with good credit to back them).

Of course, that's assuming that the cost of lost tuition on cheapo degrees is made up by bumping up the cost of good job degrees. If you merely cut the tuition of some without raising the rest, then you will need to deal with all the school's who have wildly outsized budgets that were being subsidized by the cheapo degrees.

Or, the government will end up paying for it, and there'll be a glut of social worker degrees flipping burgers because social work and library sciences have a relatively fixed number of positions available.