[cheald]

Given that you can't escape student debt even through bankruptcy, it's much harder for default rates to impact this particular bubble. You're probably right about the mechanism, but it's going to take incredible default rates to get there.

[yusyusyus]

Yeah, but you can move and escape them. Consider an educated person who is eligible for immigration to another country. This person can simply say "Bye!" and forget it. You'd almost have to tie a passport to student loan payments to keep the knowledgeable from doing this.