This is also true of loans. There is one flat interest rate for (federal) student loans. That rate does not reflect the creditworthiness of the borrower at all. It doesn’t consider their major at all. Any intelligent lender would never operate this way; who would give both a computer science major and basket weaving major the same amount of money and claim (via interest rate) that both loans are equally risky?
We have the concept of prices to serve as tools to encourage or discourage people from pursuing ventures society needs (or, really, is willing to pay for) more or less. It seems to me that in the context of higher education the economics are fundamentally broken. This causes a lot of grief for a lot of people, who then claim socialized higher education is the answer. It might be better than what we have; I’m not sure. That said, I’m inclined to think the free market would solve a lot of the problems seen in the current student loan situation in the US. There would be no kids with low-value degrees in $250k of debt graduating with a job paying $30k/yr. That simply shouldn’t happen.