I encountered the reputation angle quite a while ago, but with a different emphasis. Medieval and Renaissance merchants formed a strong network that quickly spread news of any unscrupulous business dealings — so any merchant who cheated another was soon unable to do business with any merchants. I believe that’s still the case in modern gem markets, where the wholesalers don’t bother with written contracts and don’t need to confirm the quality of the stones they receive before paying them, etc.

I suppose Graeber’s angle applies especially strongly to, say, Jewish money-lenders, who couldn’t afford to upset the Gentiles.

The debt crises are because of government pricing, particularly of interest rates. I can’t guarantee letting the interest rates float to market would cause no problems, but I can guarantee it would cause at most a fraction.

I do like the reputation stuff. It’s new to me and makes sense. Prison for unpaid debts is way, way overkill. Inability to acquire new debts is sufficient, even itself a bit harsher than necessary.