I'm not sure if I buy the whole #meta #facebook killed #xmpp. I've seen several services, with large user bases, using xmpp, or some abstraction of the same protocol. I don't think the concerns are invalid, I just think there's a bit more to it.
@aboxofsox they made XMPP (as a federated messaging protocol) irrelevant/disappear from the broader public, but they did not destroy the protocol itself, especially the client to server protocol is still used by said closed silos
@jr is it because they chose to use MQTT over XMPP? I'm not sure I follow. Maybe I'm not sure where the correlation lies between Facebook and XMPP losing momentum.

@aboxofsox they did not choose something else, but they rather gradually stopped federating with the network, when they had a big enough user base, from what was told me.

Maybe some #xmpp veteran out there could describe it better...