> Attempts to make things decentralized all seem to be aggregating into central controls, i.e. "Web3/crypto" -> coinbase, kraken, etc

Coinbase and Kraken are not "central controls" as you not only can use either and they are exactly fully interchangeable, but you can use any number of other similar services--or even deal directly with another user and keep your credentials locally--all of which are exactly fully interchangeable.