Well the Muslims did it back then and it was a success. If you're rich you lend interest-free with cost/gain sharing model. Why would you do that? Because your nominal stack of money will be depleted every year by 2.5% because of the obligatory Zakat (wealth tax). So you are encouraged to make your money work for you, hence the circular economy. If you are poor you are a recipient of that wealth tax. This was done in a gold/silver standard. There's a famous story of a Muslim leader named ʿUmar ibn ʿAbd Al-ʿAzîz who ruled Muslims for just thirty months. During this time, rich men used to come to the state Treasury, Bayt Al-Mâl, with great amounts of money, saying: “Spend this on the poor.” But they would return to their homes with their charity in hand, for it was said to them: “There are no poor that we know of”