I think the article does ask a good question — how to uncouple identity from both moderation policy and server reliability at once.
Maybe something based on SRV records could help? The user can set up just a few DNS records to establish the long-term account name being a synonym to an actual account on an actual server.
I guess Patreon supporters would get the feature of having this account’s messages be stored/shown/forwarded as belonging to the long-term name, not the local account. Message archive import could also be possible, but that would be a more long-term goal.