@navi @thisismissem Nah, the reason is pretty much that ActivityPub is a W3C standard, so pipe dreams first, implementation concerns much later so it was always seen as a guide even with ActivityPub in mind right from the start.
And the annoying interoperability parts are very rarely ActivityPub compliance issues and more often problems like "What the hell is this format, please be more reasonable" because ActivityPub barely defines behavior (as seen by the lack of MUST and SHOULD nearly everywhere).