@baldur@mhoye I mean how strictly defined is the term "social contagion" anyways? Does it cover a bunch of execs hanging out, one goes "I was thinking we should dump a lot of people" and everyone else goes "OMG I was just thinking the same thing!"
Jabber / XMPP still exists, of course. But it kinda doesn't matter. Google embraced it, funneled the enthusiasm into their chat platform which they — being Google — eventually killed, and left XMPP hanging.
This is why old gray eyebrows are raised and wallets are checked any time a big name enthuses about the Fediverse.
No idea what "sunk cost fallacy" is, but I've been writing Java for most of my life and it's okay. The thing I'm posting this comment through is also written in Java.