Well, decentralization is good but there is more to be considered than the simple count of seperate servers it seems. This article is german but it says, aproxemetly ~51% of all fediverse servers are hosted on servers from hetzner. This undermines the decentralization principles.
There are numerous factors to consider in decentralisation and hosting providers is certainly one of them, but I also honestly think that it’s also not as important. We can also argue that, for example, X% of all fediverse servers are hosted in the same country, or that Y% of them run the same software (and thus the protocol is effectively defined by its most dominant implementation) and so on.
The reason why I’m pushing back on this “not-quite-decentralised” narrative is because when we have truly centralised services such as Reddit and Twitter/X out there, it feels like disservice to Fediverse to call ourselves not quite decentralised when it’s the most decentralised solution out there that has a significant number of active users.