We can only change this if we get rid of the toxic "fediblock" culture around fedi and make it as painless as possible for users to migrate away their posts and media from their instance to another.
The first is very unlikely to happen. Turns out, making a thousand more centralized servers (which is the closer model to the #fediverse we have today) just produces a thousand people who will most likely just act as feudal lords than disinterested janitors who's just there to clean away universally-agreed upon definitions of junk. Why just be a boring moderator who does a thankless task of keeping the instance usable when you can get that dopamine instigating a smear campaign against someone you don't like by intentionally taking their words out of context or provoking them to do their worst for everyone to see (instead of you know, just leaving them alone)?
The second though, is something in the works right now for #ActivityPub. #Firefish based software like #Iceshrimp, as well as the latest #Misskey fork #Sharkey allow you to import your posts from other fediverse servers, though it shouldn't be considered 100% ready for everyone's usage every like 5 seconds just yet. It has its own problems right now I heard, like no way for direct messages to get migrated, or each old post imported now having to be refederated to many instances.