Automatically, after 30 years of pain. There is no easy answer. I'm about the last person ever to pay full tuition while working, no loans or other help. In 30 years we can make that normal, but it will take that long to figure out how, and I pity any youngster stuck in the middle while we work on it.
It isn't that fast. Even if the money stops tomorrow (which it won't - there are a lot of laws in place that need to be found and undone), universities will take a long time to adjust. They have contracts they need to pay. They are in debt to pay for those buildings and that needs to be paid. Which is why I said 30 years - that is a much more realistic timeline.
Bankruptcy protocols would be utilized. There is no mandate for US federal taxpayers to keep subsidizing universities’ largesse. If they are in debt for fancy athletic facilities and don’t have the cash flow to service the debt, that is between them and the lender.
Congress can surely do pass a law removing access to taxpayer backed student plans starting whenever they want.
So they start cramming even more students into classrooms and creating other new, innovative ways of getting money and giving the students less for it.
Without access to unlimited taxpayer underwritten loans, students will not have money to give to schools.
And one can safely assume schools are already cramming students as much as they can to maximize budget for other expenses that benefit administration.
In any case, the number of students should be declining for a very long time, so they will have to figure out how to compete for the students’ business.
Hence the solution is cutting off the student loan money spigot. Everything else will automatically fall into place.