network effect .. more like some company spends huge amounts on promotion then six months later the (borrowed) money runs out and the users end up left without a service.

regarding user experience wrt xmpp/irc/etc:

It was pretty decent a decade ago.. I see no technical reason it can't be as good or better now,

and nowdays you can add encryption or just about any other new feature you want to it.

How many times have developers out there been burned by writing an application using some centralised api only to find a year or so later that api suddenly changes or disappears leaving their application useless because it doesn't work with any other servers!