Thank you for this great article. The way that ActivityPub evolved is indeed rather unique and led to emergence of a #grassroots ecosystem.
After standardization it wasn't just Mastodon that introduced #ProtocolDecay. Everyone treading new areas did! Something important is still lacking: Robust way to extend #ActivityPub interoperably.
Providing proper guidance here (and in a 3-stage #StandardsProcess) imho is crucial for #Fediverse future. See: