I don't use IRC. But I'd never use Slack either in a project I maintain/lead. We need a better alternative.
+m quiets all users in the channel and only allows you to speak if you receive the channel-user mode +v (voice) or have +o (operator status). Some ircds also have a +h etc.
You can setup bots like “RaiseYourHand” for people who want to ask questions and need temporary voice (+v).
Try that on slack, telegram, signal, etc. Its impossible.
IRC was ACTUALLY built for collaboration and communication. Slack was built to make money.
The difference in goals causes a different outcome.
Just imagine how much better Discord, Slack, et al. could be if you could host your own instances with your own rules and with your own extensions.
I do, and I think it's a good constraint (better than the 140/280 char Tweet restriction). No excessive notifications by default, no impatient people (at least largely not because they don't tend to hang around anyway). The pace is more predictable and consistent, and it's easier than ever to have a 24/7 detached client/bouncer.
For some years, fancier services like Facebook robbed creativity and time from me but lately I've returned to a more simple flow that isn't affected by Eternal September.
IRC has a certain barrier of entry, so that tends to keep a lot of the low quality noise away (where it remains on other platforms such as Discord and YouTube).
I recognise that Slack and Discord have their own objectives, but IRC covers its own niche well.