My main thinking was not the upper 10k holders, that maybe know how and what in ( coldwallet ... ) to store your BTC, the mass was what i think about, they are using Coinbase, Binance, Etoro ... and if your Coins are there,
they are not decentralized.
When we talk about wallets, the more common terms you will come across is custodial and non-custodial. The exchanges you mentioned are custodial. They have custody of your coins and own the private keys. You only have a notion of control given to you through an account that you access with an email/username and password. But the coins are theirs. Non-custodial is the exact opposite. The service/software you use doesn't have custody or control of the keys, you do.
Centralized and decentralized is something different. Centralized refers to usually a single point of failure. For instance, if Binance's website gets hacked or taken down, you won't have access to your account any more. Because their single point of failure just failed. An exchange like Bisq, on the other hand, is decentralized. It doesn't have a central server somewhere that must store a copy of the software. Hundreds or thousands of people run unique copies on their computers and connect to each other P2P. The disappearance of 1, 5, or 50 computers doesn't result in any downtime because the peers that are online can still trade normally. And if I wanted to take Bisq down, I would have to prevent every single computer in the world to run the software. With the Binance example from above, we only need to make the website disappear.
