Like the U.S. today, the Rome economy was 'militarized', the empire over-extended, the battles fought by mercenaries. The currency might get you into the Coliseum for the 'games' but little else. Thus --bread and circuses were popular. When the Praetorian Guard auctioned the Roman Empire to Didius Julianus the sale was completed in Greek Drachmas --not worthless Roman Sesterices.
Some two decades ago, it was decided by the global financial elites that the framework for the global economy shall consist of:1) A global derivative-based financial system, controlled by the US Federal Reserve Bank and its associate global banks in the developed countries.The entire system was built on a simple principle, that of a FED-controlled global reserve currency which will be the engine for growth for the global economy. It is essentially an imperialist economic principle. Once we grasp this fundamental truth, Bernanke’s boast that the “US can produce as many US dollars as it wishes at no cost” takes on a different dimension.
2) The re-location from the West to the East in the production of goods, principally to China and India to “feed” the developed economies.
What do you think? Is the American Empire on the decline? Il Principe has often written about this. Here's one example.