Not really. I can't easily find any statistics, but I just based it on the fact that a few years ago roughly half of my techy friends used XMPP. Many ran their own servers and all of the clubs had one. The work one had hundreds of users online at all times. Today all of these numbers are zero. Roughly split 40/40/20 between telegram, matrix and discord.
Does living through it count? :)
Once Upon A Time every GMail user was also an XMPP user.
And now every Zoom and Whatsapp and meet.jit.si user is. This sort of thing didn't really go away, companies just decided to construct walled gardens instead of federate.
What server is Zoom and Whatsapp using? Their volume must be so intense I'm fascinated to know how they do XMPP for so many.
Whatsapp: seems they built their own called FunXMPP. Zoom, I'm not sure yet.
WhatsApp used to be ejabberd, IIRC, but I'm sure they're both their own thing now. FunXMPP is WhatsApp's weird non-standard compression mechanism. Basically they took XMPP and replaced eg. <message> with <m> to save a few bytes, but it's been a while since I looked into it, it may do more now.