Debt is sold "cheap" after it has gone "bad", for a lump sum. Raising that lump sum is fiscally impossible for most borrowers that have defaulted on their loans.
Also, to buy your own debt, your creditor must be willing to sell it, and here are incentives to hold onto it forever.
I don't know how the system would avoid the perverse incentive to borrow with no intention to repay, like a donaldtrump, except by tracking individual credit worthiness.
The social network of the future: No ads, no corporate surveillance, ethical design, and decentralization! Own your data with Mastodon!