By this definition, the current financial system is also decentralised. After all, if one bank fails, a new bank could very easily take its place. Even our system of central banks consists of a relatively large number of more or less equal peers. If the US central bank fails, I'm sure "the economy" will be more than happy to change things up radically and reassign some of the global influence on the financial system that the fed currently has to competing nations' central banks.