On the increasing number of accounts, it could as well be due to a rise in spam that we have seen on XMPP.
https://yaxim.org/blog/2017/12/22/spam-reduction-on-yax-dot-...
https://www.bleepingcomputer.com/news/security/xsender-the-s...
I guess the eventual problem here is that everyone affected will turn off reception of messages from strangers. That would make XMPP somewhat less useful as a general method of getting in touch with someone.