In this particular case, it is a somewhat circular argument. Identify education that would benefit society. Give it away for free. Watch society become more wealthy. Everybody wins. I'm not convinced that the list of "education that would benefit society" is as limited as the current STEM obsessives would have us believe, but it's a starting point; it also doesn't have to be just university education. Nationwide shortage of electricians, for example? No worries. Free electrician education ahoy.
The only problem is that this practical, pragmatic approach violates some people's morals. Similarly to how the US could have a far cheaper, far more effective corrections system, but that be morally objectionable for too many people.
On a personal note, I'm not convinced that the end of high school is the correct cut-off point for free education (particularly given that the US has become a far more technological society and economy over the last century), but I don't have any evidence for that. It would seem something of a suspicious coincidence.
The only problem is that this practical, pragmatic approach violates some people's morals. Similarly to how the US could have a far cheaper, far more effective corrections system, but that be morally objectionable for too many people.
On a personal note, I'm not convinced that the end of high school is the correct cut-off point for free education (particularly given that the US has become a far more technological society and economy over the last century), but I don't have any evidence for that. It would seem something of a suspicious coincidence.