To late to edit here, but an additional thought: If Bluesky starts getting traction, a move to undercut it from Fediverse proponents would be embrace and extend: Augment clients with webfinger, provide bridging to the Fediverse, and generally aim to make Bluesky users expect to be a part of the wider Fediverse. Only if Bluesky very rapidly overtakes Mastodon to the point of dwarfing it or remain an irrlevance, will it have a realistic prospect of remaining what they want it to be rather than turn into some hybrid that runs away from them.