I would say commercial banks are on their way to being challenged by DeFi and stablecoins on Ethereum. But it is debatable how decentralized this system in its entirety is given the biggest entities are centralized custodian coins. But still.. massive disparities in yields and flexibility of moving value around at will does have enough disruptive force that banks and the Federal reserve are racing to both regulate stablecoins and push "CeFi" instiutions into registering as banks themselves, while on the other end legacy finance is moving towards adopting some of these systems themselves.