At first, our solution appears to be not good enough. Having one currency for everybody seems to be the ideal way. But note that clustering is a common technology in computing and it is now widely used. There is simply no hardware capable of writing 56,000 transactions per second on a single node. When the problem can't be solved on a single computer (and Ethereum is a computer, but virtual), it has to be distributed between many computers. Dividing has known as a successful strategy for ages, and it is not going to fail us.