The reason why student debt is basically unheard of in Denmark since college is free (although to make that happen, the Danish government poses high taxation towards citizens like they do in order to maintain stable social security nets like subsidised healthcare and public housing, also why they have less homelessness).
Mainly Danish, Swiss and European citizens are eligible to study without stressing over student debt upon graduation. It stems from this: Danish government is more on for the people while American government is more on caring about themselves plus nepotism on the side (MORE & HIGHER TAXES TOO ON TOP OF THAT).
It would not work because an educated populace is harder to control. Uneducated people will be easily manipulated to fight amongst themselves while the oligarchs do whatever they want