It's wise to view a degree of such cost which is unlikely to re-pay itself as a luxury good. We call most other quarter-million dollar products that have little investment potential, such as yachts, luxuries. The whole point of free college is to give everyone a shot at the middle class. Personally I think we'll just get degree inflation; college has been used as a distinguishing factor because there are a limited number of such jobs. That aside, basket-weaving degrees don't move people into the middle class. Would anyone, progressives included, contend that everyone ought to get a free yacht (or other luxury good of your choice)? A free stem degree is at least much more likely to lead to long-term, multi-generational success.
Markets provided some balance here, but were taken out of the picture. No thoughtful lender provides equal capital at equal interest rates to a poetry and a business major. This is reasonable, as the business major has a significantly higher lifetime earning potential. Making more capital available at lower rates to higher-earning majors is a good strategy because it helps to push people into higher-earning jobs. The invisible hand seems better-equipped to do this than a central planner.
I haven't seen ISAs (income-share agreements) mentioned much here, which is a pity. The obvious solution is to modify the incentive structure such that colleges have a strong financial interest in the success of their students, which ISAs accomplish. If you want to read more, I recommend this article: https://reason.org/commentary/a-better-path-to-dealing-with-...
Purdue is currently offering them, so we'll hopefully get some real-world data on how they work, but they seem very promising on paprer.