[MattJ100]

As someone who worked on an XMPP web client that set up a whole session in a single HTTP request and response, I can say it's definitely possible to do this.

XMPP also has optimisations so you can resume a session across network disconnects etc. so that session initialization is typically limited to app start.

A more fundamental issue for many of these apps is that XMPP group chats were very presence-focused, and quite chatty (you need to join and sync every channel every new session). People have worked around that in various ways in the past. These days we have the newer 'MIX' standard for group chats which is not per session and far cheaper for many/large groups.

XMPP has evolved, and continues to evolve. But I fear that people inventing their own chat protocols is a problem that can never be fully solved.