These graphs show that while some Americans (most of whom are college graduates) are doing very well, just having a degree doesn't guarantee you a good or rising income.There is also the issue of schools offering worthless degrees. Krugman directs a lot of animosity at for-private colleges, some of which are pure scams, and some of which are just charging a lot more for credentials available at community colleges. But there are other cases. To become a fully credentialed archaeologist you need a master's degree, which is expensive at a decent American school. So we see a lot of young people who have gone to Britain to get one-year MAs on the cheap. So far as I can tell these programs are set up simply to extract money from foreigners, since the students usually don't learn much and what they do learn is irrelevant to work in North America. We pay very little attention to those degrees. Now, if you managed to land a job and then get the necessary experience and learn the necessary skills, that MA would count for the bureaucratic requirement that a principal investigator have a graduate degree. But in and of itself it means nothing.
Which means that young archaeologists face the grim math of having to borrow up to $30,000 to get a job that starts at $50,000-$60,000 a year.
While I understand the anger over all of this, I am opposed to debt forgiveness. College graduates are not the most needy or deserving people in the US; I would rather see some of that money spent on mental health care for the homeless, and I could come up with lots of other examples. It also has the perverse effect of rewarding people who borrowed more than they really had to (lots of people do, and use the money for living expenses) while punishing those who scrimped and borrowed as little as possible.
Most importantly, what is the long-term plan here? Declare a debt jubilee every decade? Maybe, instead, we should be do something to rein in college costs so people don't have to borrow so much? Or how about we make community college free, and encourage people who would have to borrow money for school to spend their first two years in CC? There are many better ideas than just waving your hand over one generation's debts.