AIM, Discord etc. have the 'word-processor problem': the protocol and the interface are inexorably intertwined. You're stuck with whatever user interface they provide.
And this 'word-processor problem' is compounded by the 'normal people' issue, or, even worse than that, the 'lowest common user' problem. It's optimisation not for the best or the most powerful or even the prettiest interface, but rather optimisation for ease-of-immediate-use. (I.e. the interface for word-processors, whether LibreOffice or Word, are miserable environments for actually creating in, because they're tailored to not even 'average users' but to 'inexperienced and lazy users' - those who want to be able to sit down and use it without any training.)
With an open standard, you can have good interfaces for 'normal people' and an interface for 'lowest common users' and interfaces for other types of users, and this enables all of these types to be able to interact.
Please show me a cross-platform good interface for "normal people" for either IRC or XMPP: that supports all the latest standards and is on par with, say, Slack. Where cross-platform isn't Windows-Linus-Mac, but desktop-mobile.
For IRC I'm aware of none (except the ... closed-source web/electron-based irccloud, the irony). For XMPP there's just Conversations for Android, and that's it.
I also like the tech bro considers "normal users" to be bad, be cause there's "even worse than that, the lowest common user". There is a reason why people don't use the crappy half-baked barely usable crap that tech-bro non-normal above-average über men produce.
"Back in the day" they had no choice or little other choice but.
And even then "normal people" would prefer things like AIM and ICQ for reasons obvious to anyone except the self-proclaimed not-normal above-average über-men.