I know folks who have worked towards PSLF and ended up getting screwed because they weren't on the right repayment plan. Absolutely devastating to find out you've spent ten years working on something only to have it fall apart because you checked the wrong box once. And apparently this is a very, very easy mistake to make.

Particularly a while ago it was nearly impossible to utilize the program because it was a bureaucratic and underfunded mess. So the number who qualified was effectively zero.

Now it's marginally less terrible and actually forgiving some people's loans.