The debtor doesn't necessarily fail. Imagine you bought a house with a 6% mortgage and hyperinflation hits at 18% who is loosing the money? the lender... Who is more likely to go broke in this scenario? In the case of US and china the situation is more like the home builder who spent money on raw materials which ate up his margins but you got a bargain house because he really needs to sell it so he could hold the paper and balance his costs with the mortgage payments... Now imagine if the costs exceed them he is in a dark and painful place especially if he has to convert your payment and the currency you are paying is falling in decline in relation to the currency he spent on the building of the house and raw material aquisition...
Rome had to import grain to feed itself and had no infrastructure that dealt with social problems ergo 25% citizenry in italy itself with rest being slaves or non citizens whom helped destroy it indirectly mostly.