What became painfully clear to me after a while was that the big guys (AOL=AIM+ICQ, MS, YAHOO) who were running the show were all actively making sure that no standard would be decided upon. It was all dressed up in technical arguments, so it didn't look that way, but it was. Perhaps the engineers participating in the discussion weren't even aware -- it's easy to miss the big picture -- but as an outsider it was painfully obvious that the effective mandate that was given by the respective companies to their representative was to NOT standardize anything.
What ended up being the IETF standard was Jabber -- which was way too complicated and wasteful. And the reason it ended up that way was that while the big guys were avoiding standardisation, someone just put out an open source / open spec product which -- with all its deficiencies -- eventually worked well enough to gain non-trivial adoption, including by the IETF. And all of that happened awhile after the instant messaging working group was disbanded because of "irreconcilable differences" -- those differences being that every participant would only accept a standard that forced others to concede defeat and implement that participant's existing system (always in a way that limited everyone except said participant, of course)
Watching those discussions was an eye opener about how things supposedly work (and even look that way on the surface), and how they really work.
EDIT: REMOVED claim that Jabber/XMPP is still too complicated. I'm sure it still has 90% bandwidth and parsing overhead compared to comparable protocols (unless it's become backward incompatible), but standards have changed, and I guess that's no longer considered wasteful or bad engineering practice.
EDIT: ADDED: Just to be clear, this is an anecdote about the distant past (as in, 12 years ago now!). I have not been following Jabber/XMPP closely since 2004 and not at all since 2006 or so. Back in the day it was ill-and-under specified, ridiculously chatty (as in >90% overhead before you count TCP headers, both in bandwidth and parsing). What is acceptable has changed since then (no one cares about 95% overhead anymore), and for all I know all the kinks have been worked out.
And for the good parts - it is out there, there are multiple server and client implementation, and it works. That's a thousand times better than the product I was working on at the time, which was proprietary closed source, and though it was super efficient in every way, was discontinued and is no longer available.