By this definition, isn't for example USD a ponzi? Afterall, it is a Fiat currency now and not backed by a commodity. If I received wampum back that would offs

By this definition, isn't for example USD a ponzi? Afterall, it is a Fiat currency now and not backed by a commodity. If I received wampum back that would offset it no? How does taxes/gdp protect you if taxes are of their self made up of USD.