Agreed that these other issues were a problem for XMPP. Christina Warren made this exact point on Mastodon a few hours ago -- in response to a post from Evan Prodromou that talked about the role that spam and harassment played and how he and others in the XMPP community didn't diversify the network. So, there are multiple factors. That said, I still think the post I linked to is very much worth reading.
It is a valid opinion, and the events described there took place, I just - personally - don't believe the outcomes were caused by the events described, they feel more like coincidences to me. Although Google dropped XMPP at least partially for the same reasons it died - trouble with architecture that made it problematic mobile.
And the comparison is not fair. XMPP was meant to be extended, so complaining about the second "E" in "EEE" is IMHO questionable. Google left a bunch of useful XEPs and even a Free Software codebase (libjingle) that others still use to the day, and I don't see anything wrong with this (and I'm surely no fond of Google, but that's not something I'd bash them for). This is feels very different from what may possibly happen in the whole Meta/Threads/Fediverse/ActivityPub situation - I mean, it's not likely Meta starts contributing to Mastodon project or something. In my understanding, EEE is more applicable to Microsoft and IE (where it surely happened, and a lot) than to Google and XMPP.
IMHO the article is a good read to at the very least be familiar with the events and understand the argument - but personally I find myself disagreeing with the presented arguments, thinking it's quite a stretch. Of course, that's my own, purely subjective opinion.
Yeah when there are multiple causes it's hard to know how much each contributed.
AcitivityPub's also meant to be extended, there are FEPs, and it's likely that the working group will come up with a new version as well. That said there certainly are differences between XMPP and ActivityPub, most people say the ActivityPub ecosystem is significantly farther along than XMPP was.
I could imagine Meta doing an open-source AP server (and with a fresh start it would be cleaner base than Mastodon). I also wouldn't be surprised if the release a app building toolkit / framework / whatever ... there isn't a good one now, they do that stuff well, and as they introduce proprietary AP extensions then they toolkit is a good way to get people to adopt them. But it's very hard to know at this point, it's also possible it's just PR spin and they won't really invest in it. We shall see.
