Remove the option of student loans, especially those backed by Uncle Sam. To be sure, there would be fewer students, but then there would be huge competition for the rest. Perhaps it would even make a college education affordable. On the other hand, it just might result in the downsizing of many schools. It might even result in some closing their doors.
Many professors would take pay cuts. Some would even need to find another job, which might not be such a bad thing for American society. I mean, when you consider their contributions or the lack thereof.
Of course, it’s all pointless to consider. It would be easier to solve drug abuse problems than the dependence on student loans.