Back in the day, IRC and Usenet were all there was. We used them because it was that or nothing. Today we have a lot of choices and many people – especially folks whose primary industry is not software – don’t want to use clunky, text-based systems like that. In addition, they are really pretty poor from an admin/moderation p.o.v. which is often a big concern for folks trying to manage working groups online (the Rust IRC channels on Mozilla’s servers were constantly getting spammed by drive-by hooligans and no one seemed to be able to prevent it).
I’ve been online for about 30 years and, despite fond memories of IRC and Usenet decades ago, I’m glad there are more friendly options available these days!