How is Ethereum Developers Community organized?

Hi!

The development of blockchains has encouraged the emergence of new organizational models based on decentralization.

Of course, decentralization is measured on a broad spectrum and there is no solution that is 100% decentralized. Ethereum is no exception, and we know that some groups are more influential than others (Consensys, Ethereum Foundaiton, etc.) in its development.

Of course, other open-source projects have relied on communities of developers spread across the globe. But I hypothesize that the development of Blockchains is even more complex because it's not just about managing the source code but it's also about managing live deployments with hundred of millions active users and a lot of $$$$$.

So I'm wondering how the whole Ethereum developers community organize in order to improve the software (I'm not including dApp developers ; only Ethereum & L2 Core developers).

So I'd like to know:

1/ To what extent does this decentralization fit in with current Ethereum development practices in the broadest sense?

2/ In concrete terms, how are these communities organized to ensure the coherent evolution of Ethereum and scalability solutions, while enabling a form of openness and decentralization (what ceremonies, calls, tools, etc.)?

Can someone explain me this like I'm 5?

Thanks!