>We can say the same thing about K-12 education -- it's just something we choose to fund collectively, because that's the kind of society we want to be.
But in K-12 education, the taxpayer/state has strong control over what's taught. In the last few years there's some latitude by the students, but nothing close the panoply of programs offered by universities. If education is state funded, but only for programs with proven ROI (eg. STEM), I'd be fine with that.
When the state pays, what matters is the ROI to the state. There is a need for teachers, social workers, and people familiar with various cultures, but the market will never pay them well.
Public funding models often have incentives for delivering the degrees the state wants. For example, there could be field-specific quotas for degrees. The university gets paid for each degree up to the quota, but not for exceeding the quota. That can have interesting effects in fields that are popular but in low demand. For example, the acceptance rate to psychology can be as low as 2-3%.
But in K-12 education, the taxpayer/state has strong control over what's taught. In the last few years there's some latitude by the students, but nothing close the panoply of programs offered by universities. If education is state funded, but only for programs with proven ROI (eg. STEM), I'd be fine with that.