But that comes with a trade-off that your identity is permanently tied to your server.
That's why account migration is lossy and why you need to create a new account just to change your handle.
Au contraire! Even without webfinger, the Activitypub APID starts out with
https://yourinstance.com and you aren't allowed to publish digital signatures, so account migration is lossy no matter what you do! If your instance bans you, or goes down forever, then your followers are gone gone gone!
Seriously though, I think you're talking about the "did" schema in general. "did:web" certainly is no better than "
https://yourinstance.derp" and
the many DID methods each with a shitty corporate sponsor are mostly just shitcoin blockchain bullshit. However, certain methods such as "gns" and "ipid" do use public keys in a uh... very complicated way. Those could (in theory (technically)) let you migrate accounts seamlessly, or even have multiple accounts on multiple instances all associated with the same identity.
There's also
the Identity Proofs FEP which would make account migration super seamless, but you couldn't have multiple simultaneous instances.
And in all cases, webfinger can just return that URI when queried for at who at what instance. Any mentions would resolve to the public-key-based ID in the JSON, as long as the instance was playing nice at the time of that post's creation. So webfinger is not a huge deal. Messy, but how else are you going to turn a mention into a URI?
Personally I'd like a client that didn't have mentions in the post content at all. Instead, you have a second interface where you can add people, like with email "To" and "Cc." Then I'd make it so my client remembered public key based APIDs, so if you typed
@myfriend it would autocomplete that to
@myfriend@12345678901234567890... without querying your friend's last known instance.
It's just ... the only public key based APIDs are those "DID" things, which are super overcomplicated and skeezy. Isn't there a "PGP" method for DID, or something?
CC:
@mastodonmigration@mastodon.online @baralheia@dragonchat.org