Has anyone ever considered that Threads might actually WANT the fediverse around? If you look at the Epic vs Google thing and more importantly the plethora of EU regulations that try to force big tech into being more interoperable, break up monopolies and allow users to move away from forced defaults, being connected to a working fediverse (instead of destroying it) seems like a pretty decent insurance policy. You connect to a significantly smaller network that poses no tangible threat to you and is to a large degree made up of unmonetizable privacy and open source nerds anyway and you can then conveniently point to that whenever regulators try to claim you're being a monopolist.
