It’s not essential for me that these different platforms talk to each other. A microblogging platform doesn’t need to (maybe even shouldn’t) integrate with a forum or vice versa. Each has its own role and muddying the water doesn’t bring any real benefit imo.

The fact that they are decentralized is what’s important and the fediverse makes that possible for all platforms built upon it.

Moving an account from one instance to another is a real issue though, I agree with you there. Defederation would become less of a problem if you could easily move your account (with its post history) and communities you moderate to an instance that aligns with what you’re looking for, assuming it exists. Ideally everyone would have their own personal instance, but that is probably not feasible for most people.