I hit 'found the answer' by mistake.  This answer sounds very theoretical; based on your understanding of how the world works, that small banks would be quicker to react than big banks, you say decentralized banks could survive and prosper.  Another way the world works is that when an industry is dominated by a few large players, they will compete with each other but also manage to cooperate in keeping other players, who do things differently, from getting a seat at the table.  This attempt usually succeeds for a while.  The centralized banks would work together to buy control of the decentralized banks one by one as the latter had runs of bad luck, mismanagement, or strategic choices that turned out to be wrong.  The US would wind up being economically colonized by the countries with strong central banks.