Lot much is said about decentralized environment but only btc is purely decentralized rest are just created by teams and there is no guarantee of there decentralisation. Even we know that ethereum blockchain is created by a person and who knows he has the loop hole to take control one day.
Btc was also created by team but the only difference is they are anonymous to you but that doesn't mean they are not aware of what is happening (i.e if they are still alive) so you can not say btc is purely decentralized when it was created by a person or group of people who decided to stay unknown. btc is decentralize and open to the public but it was created by a human(s).
Supposing vitalik and the eth team decided to also stay anonymous when the created the ethereum network you will also have the same perception towards eth.