Well, with the announced (but not yet issued) Executive Order on student loan repayment programs, that could be said to be less than $1T, because Obama has unilaterally shifted some of the burden from student loan borrowers to taxpayers. In the federal guaranteed student loan world it's a zero sum game, what the student does not pay the taxpayer does.
And WHY do they have this amount of debt? Because they did not save anything for college. Because they did not work while in college. Because they did not live under any sort of reduced standard of living while in college. Because they elected a non-marketable major resulting in a poorly-paying job.
These stories never explore the “why” of people “finding themselves” in unfortunate straits. Yes, some come into hard times through no fault of their own, but far too many are totally responsible for the spot they are now in.