The idea that there was a community that disappeared is a myth. The same one that always existed is there: the people who really want to use XMPP federation are still using it. People are just mad that a wall went up between them and their non-tech friends and family at Google and Facebook.

The big federated instances like Jabber.org are still around. My account is still there since I first created it in like 2002 or whatever.

But as far as XMPP usage in general goes:

- ProcessOne and other companies specialize in providing XMPP expertise and make plenty of money doing it.
- Billions of people every day benefit from XMPP being used to transmit data without their knowledge
- lots of VOIP/SIP things end up using XMPP for the messaging transit
- WhatsApp is XMPP
- iMessage is XMPP
- all push notifications on Apple and Google devices are XMPP (APNS and FCM speak XMPP)

XMPP Federation was a *feature* of the protocol, not a requirement. The same can be said about ActivityPub.