I recall working at companies where the ops or DevOps teams would run their own IRC servers pre-slack. It was basically the only way to get stuff done if you had a desktop PC and needed to work closely with anyone. The problem is that most companies don't know how to do due diligence on a tool like IRC and the clients aren't very friendly. The lack of commercialisation of the space is what prevented companies from paying for it, and that meant no easy and rich clients got built, which meant it never got commercialised, etc etc..