I can understand him bailing on Bluesky if he wants to focus on billionaire "philanthropy" or he's just fucking tired of working (wouldn't you be?) but it doesn't explain the Twitter presence.
He's also apparently putting a significant amount of money into Nostr.
I think his big problem is with the audience Bluesky attracted, to be honest. It seems like exactly the opposite of what a techno-jerkoff like him wants to see.