Are we decentralized yet?

Can someone explain how Fediverse instances or any decentralized platforms deals with most obvious issues of decentralization? Like if I join some node then one day it's offline and all my data lost. I mean surely instances usually don't disappear without notice but it still a totally possible thing. Or what about those times when entire instances get involved in dramas and end up defederating? I don't want to lose my connection with potential friends from such instance just because of something like that. I even remember some time ago when there were news about Threads being federated some people deliberately gathered "signs" across lots of instances to collectively defederate from Threads and it's just ridiculous to me that this even happened. What all this talk about fighting censorship while actively engaging in constant "self-censorship" making own echo-chamber as tight as possible?

In ATProto, this is solved by not having "instances". Your data is stored on a personal server (which can ofc go down). However, your identity isn't hard-tied to that server. If you have a backup (making those more easily available is being worked on by people in the ecosystem), you can restore it on another host and point your identity there instead. So there's one level of indirection which prevents the problem you're describing.

Additionally, since ATProto decouples hosting of data from hosting of applications, there is no such things as "instances" having beefs and defederating from each other. The data flows one way (from PDS to apps). Apps may choose to ban certain PDS's but generally PDS's themselves are treated as app-agnostic containers of data. So intra-network social beefs don't translate to technological cutoff or loss of mobility. Social groups and communities are decoupled from hosting.