I am invariably going to see in the world of Slack, "IRC, why don't you die already". No, IRC is not going to die. FreeNode is alive and well. And while you busy slamming and wishing death of IRC, just check the memory usage of your Slack client.
Both failed to modernize or keep up with progress. The only places where this stuff is at all still used/tolerated is places where the average age is well above forty and where the audience is engineers only. Most millennials that I work with don't even know what this stuff is because they simply never encountered anything where this is still in use. The ones that do tend to be male and heavily involved with OSS. It's a somewhat elitist thing at this point.
People seem to like to hate slack and similar solutions. The OSS way to deal with stuff like this is to build something better and not get too nostalgic about decades old stuff that did not keep up with a changing world.
Here are the design goals for a modern team chat solution: - It must be stupidly easy to create a private team. Think minutes. This is not something you put an engineer on either. That would be a waste of time/resources. - There must be zero admin overhead. This is the first thing you do in a new project. SAAS is the way to go here for most places; sign up, click, click done. There's absolutely no excuse to waste any time setting up software, servers, and committing to managing that for the vast majority of teams. - It has to be inclusive. Anywone should be able to jump in. Especially non technical people. Like your manager, designers, users, etc. - It has to have mobile apps that are usable and fully featured.