But money would not disappear, money would go into universities and education! It will fund new campuses, research, stipends...

Imagine how many students from Africa could study at US universities, if all student loans were repaid. That could really restart economy!

Government has good ways to collect money. For child support debt it can confiscate driving license, passport, throw people into jail... Or even prevent people from quiting their jobs! University educated people have money!