Like I said before, all of that is non-standard functions that the vast majority of the fediverse doesn't even support.
I think you might be confusing ease and possibility. Few people even when moving instances within the fediverse are going to have that option (save for those moving between two instances of the same platform).
It's not whether there's some convenient tool to move your posts or other data.
It's about whether after the move you can still get the same updates and talk to the same people.
Think of it in terms of the oldest surviving federated network: changing email accounts.
Before SMTP (the federated email protocol), you had to have accounts on every server with people you wanted to talk to. After you only had to have one account, but could readily move about the network to other servers if you got fed up with your server's bullshit or another offered better services.
(And for the record, public bridges with no opt-out methods exist for email as well)
@HistoPol @jamie @oliphant @snarfed.org @luca @PCOWandre @chronohart @snarfed