I'd rather have the privilege gained from education taxed at the time it is actually received than at the time of studies. It seems like a fairer approach, as we should recognize that not all education leads to the same level of monetary privilege. I.e. compare salaries for nurses, teachers, engineers, doctors, MBAs, etc.

Most people have to take out loans anyway to cover living expenses. I don't think there has to be any further disincentive for those from non-wealthy family backgrounds.

Not all students go on to become particularly privileged. Many fields require educated employees yet can't pay for those.

Also, in many places the state himself requires some level of university education for some positions. Essentially instituting a cost of access for government employees is a scary proposal.

Finally, price discrimination means shutting up the universities to the poor ; making the university education premium yet higher, and going yet more disproportionately to those already well off. Since the state is anyway going to subsidize university, that would mean an even more regressive subsidy.

Un roi sans divertissement est un homme plein de misères

Many people are not willing to take debt, because it is associated with a social stigma to be in debt. So it does scare away students, even when you have a special system, that would prevent unemployed from having to pay back. It is not rational. But you have to run your country and your economy with the people that are there, not with fantasy people, who behave perfectly rational.

Der Amerikaner ist die Orchidee unter den Menschen
Volker Pispers