I wish college credit hours would be billed based on the potential income of the degree. My ex wife was a family studies major in college. It was training to teach preschool or running housing for disabled people. The degree trains people to provide a needed service but from a monetary standpoint is peanuts compared to a STEM degree. The tuition was the same though.
So she has a degree that is valuable but moreso from a benefit to society than her checkbook. When we were married I was responsible for her student loans because there was no way she could pay them off. That was fine and now if she can't that's not my problem. But she wasn't that bad in the hole. It was 25K or so. Her best friend had double that. Those aren't insurmountable unless your job prospects pay you 30K per year with no realistic bump in pay.
I don't disagree that schools give degrees that are worthless unless your goal is to get a doctorate and chase academic butterflies but schools also give out degrees that are beneficial to society, but not in a way that gets the degree holder paid.
Would your basic premise not wipe out many, many degree fields? Seems like a slippery slope if schools stop dropping programs, which is what will happen if their allocation of tuition is decreased because it is deemed non-essential or with poor future income prospects.
Would a big part of the problem not be solved if the loan underwriter had a couple checkboxes on the application that ask what your degree studies are, what your professional aspirations are, and what your financial expectations are, and make a loan accordingly? I know if I buy a car I have to tell the bank what type it is and they look up its KBB value, depreciation expectations, etc. and make a loan accordingly. Might also steer people away from some fields if they realize they are not going to get but a portion of the loan otherwise.
But again, I could see that process still killing many degree fields.