I’m a lowly SRE, and I’m not technical enough to use IRC effectively despite on and off attempts spanning more than a decade. Believe it or not, I’m not the least technical person in our org! This, I think, is the biggest reason my company, and presumably many others, don’t use IRC, never mind that running your own IRC or Zulip or whatever doesn’t inherently gain you any extra uptime and in all likelihood costs you more uptime (who is going to be better able to support your application, your Ops team with dozens of other critical applications to worry about and no inherent expertise with the application, or the dedicated team with deep expertise and a reporting structure all the way up to the CEO who are singularly aligned with the goal of running this application? Note: this argument tends to apply to any managed-service vs self-host debate. Note that we wouldn’t have a debate at all if every Zulip/IRC/etc outage hit the front page of HN. :)