As far as I know, Mastodon didn't really set out to solve that particular problem. But it does seem like ATProto did, as it seems a lot easier to move around in ATProto than Mastodon (and ActivityPub in general).
replyYep. Changing servers is easy. You just have to update the central PLC registry run by Blue Sky LLC to say which server you're hosted on now.
reply... wait a minute.
You're complaining that moving away from a PDS means you have to let that PDS know you're moving away? Do you understand what you're actually complaining about, or I the one who misunderstand what you're complaining about?
replyIn case you haven't read them before, the docs for migrating are here: https://atproto.com/guides/account-migration