Fediverse memes

This whole instance-tribalism seems very self-defeating to me. Why be decentralised if everyone ends up so boxed off that there are just a handful of isolated instance-clusters talking amongst themselves? It's like how email (SMTP) is decentralised but the mega-hosts act like a cabal, gatekeeping so strongly (and virtually doing blocklist-by-default for unrecognised servers - even of good standing) ultimately capturing the user-base by undermining the decentralisation. Luckily with DKIM/SPF/DMARC/ARC/etc and stronger anti-trust regulations email seems to be slowly climbing back out of that hole. Unfortunately with all the banal tribalism it feels like much of the new Activitypub based tech users are willfully climbing into that same hole, without even being corralled there by mega-hosts.