The source of the 2007 crisis was private debt and not sovereign debt. The failure of neoclassical economists to understand what money and debt mean and how they are created and interconnected guarantees another crisis coming. 
And the fact that student debt is treated so differently from other kinds of debt (mortgages, credit cards, business loans, etc) is evidence that student loans are being used as a literal shackle placed on the necks of young people so they do not rebel. Ironically, such shackles were, historically speaking, the main reason behind rebellions and revolutions. 
Good sources to look up are Steve Keen (on money creation) and David Graeber (on debt and its meaning).