In practice, crypto markets are not any more decentralized than others. In real life people use hosted wallets on exchange platform. Transactions happen on a distributed (not decentralized!) ledger. The underlying network is only somewhat decentralized (the mining economy tends to the concentration of big players).
Also the way you seem to imagine we could be "removing the banks, exchanges, brokers, clearing houses, compensation chambers, back office, etc." just shows how much you don't know about how an economy works. Real-world transactions need to be reversible, need escrow, guarantees and a lot of other mechanisms that are by design not available using blockchains based assets (if they are there, it means the assumptions which would have made a blockchain useful have been broken, and that we can achieve the same features and services without a blockchain in a more efficient manner).