Because forgiving someone’s loan means you don’t get what’s owed you, and you have to suffer the consequence - not the debtor. Also, just because you forgive someone’s loan doesn’t mean the creditor you owe money too will forgive your loan. ...and hence the natural consequence of this economic quandary being war: “you WILL pay me back, pound of flesh if need be.”
Methinks this is why the Old Testament commands a “year of Jubilee” where all debts are forgiven every 49 years: it’s gonna happen one way or another every half-century (being human nature and economic cycles), so may as well do it in a predicted, specified, organized manner.
Well, if we owe (for example) China 500 billion, and China owes Russia and England 250 billion each, and England and Russia owe us 250 billion each, can’t we sort it all out with collapsing the system?