You're paying attention to outliers. Most people don't have astronomical student debts, and most that due are in general in extremely high paying professions. Student debt is a problem, but most people do no have 100k in debt for creative writing, etc.

The easy solution is to limit government student loans to 20k and be done with it.

There is roughly 1.6 trillion dollars in student loan debt owed. 40% ($640 billion) of that will be defaulted on. There won't be any large derivatives markets set up to eat it like there were with the mortgage lending crisis. The people who will end up footing the bill for this won't be insured banks, it'll be John Q Taxpayer, and the economy writ-large. Even limiting to $20k per person won't solve this issue.