Edit: see this from the FDIC, which suggests this would be an option for depositors https://www.fdic.gov/consumers/banking/facts/borrowers.html
If it turns out to be a crime, I think I’ll take my chances with a jury trial where all have to agree to convict.
If the bank repossessed my house, for example, I would not continue paying my mortgage.
The same reason there is to pay any debt. Damaged credit, judgements, seizure of assets.
This is literally what this thread is about, people's debt getting passed on from the bank to someone else
It doesn't work the other way around: if your end of it is a liability (your loan/mortgage/whatever), nobody wants to buy that from you, because it's worth a negative amount of money, it's a burden, a liability. Companies want to purchase the other end of the deal, because it's what makes them money: it has a positive value.
So depending on the the loan, you might be able to buy it so you can pay it off at a discount.