bluesky is more federated than threads, but less federated than mastodon. As I understand it, you can more or less host your own bluesky "instance". Though it is difficult to do and some parts you have to build yourself, it is technically doable. This is not the case on threads, I believe.
Lemmy instances regularly go down for maintenance longer than this.
Twitter used to regularly "fail whale" and in the long run no one cares.
Yes, decentralizing is a good thing. Yes, it's fun to poke at BlueSky. But in the long run if you have a product that people want to use then they'll put up with a lot of crap/downtime.
Assuming people dont make multiple accounts and each server goes offline for maintenance for the same time, wouldnt both one server and multiple servers act the same for the user?