You don't need everyone unless you're trying to IPO. For instance, it's not hard to slap mature GUI clients on company laptops to access a company IRCd. You can even use emoji!
>You don't need everyone unless you're trying to IPO
But if you are looking for people to talk to, but they don't use IRC (read: almost everyone) there is no reason to use IRC. If I wanted to talk about speedrunning a game I will go to Discord because that's where the community is, not on some IRC server.
Slack doesn't get money from casuals, so if your company says "hey we use IRC," you're going to plop a client on your laptop and be done with it (and there are web clients besides). It's not a learning curve you'd have to worry about.
Quassel? Mature and works on everything except iOS if you use the split client/bouncer mode.
iOS is only not properly supported because the devtools and hardware are far too expensive for me to finance.
If you wanna deploy an ircd, there's some modern ones like ergo. Deploying ergo and the quasselcore bouncer can be easily done with a helm chart on your k8s cluster, you can even get Prometheus metrics out.
