By the very nature of cryptocurrencies, they can't prevent anyone building a centralized company around them, and I don't think that was ever the intent. The permissionless, decentralized properties are important in the following respects:

- anyone can transact with anyone on the blockchain

- the fed can't print more of it

Anything else is a disctraction.

Besides that it's pretty obvious that Coinbase is centralized, regulated etc.. mainly because it deals in USD, not Bitcoin or Ethereum.