The effect of riba' on the overall economy is quite strange, it ultimately causes the existence of more debts than money to pay. I once read a study of American Indians, Peter Farb's "Man's rise to Civilization", and one section tells us about the Northwest Coast Indians who build totem poles and practice usury. It was a pretty extreme case of usury and society. They used woven blankets as currency, and borrowed and lent to each other with high interest. There were only about 500 blankets but the total debt reached millions! The author noted the system was prevented from collapsing because the tribe valued social prestige and rank, and forgiving huge debts (by destroying its record written on a sheet of copper) caused one to increase rank and prestige. It's an extreme but very interesting case. Now I do wonder about the IMF and other banks periodically "forgiving debt" while still perpetuating usury... maybe they do it to prevent systematic collapse and increase prestige at the same time. So every time it happens, it means the system is actually teetering on the edge...