It's not like you're stuck with ugly terminal only clients anymore. There is KiwiIRC, IRCCloud, and several other great web clients that not only let you connect to any server but provide bouncer services and backlog. There are also plenty of easy to use native clients that don't require any configuration.
There are some benefits of Slack, but the ones you mention aren't them. In fact, seeing how you CANT host your own Slack server I would say "difficult to host" is a flat lie against IRC.
(No I don't work for them. Self-hosted their AMI at last job, found them to be friendly, easy to deal with folks)
I can tell anyone in any kind of role (senior to junior, technical to non-technical) on my team to "Download (the/a) client for X and join #channel #channel2" "Follow the directions to set it up so changes on this Trello board are posted to #channel" and reasonably expect they will succeed if X is Slack, but not if X is IRC.
1. Download IRC client.
2. Pick a nickname.
3. Pick a server.
4. Join a channel.
With something like kiwiirc, you can even omit steps 1, 3, and 4: you can give someone a URL to a particular channel on a particular server. Just pick a nickname and click "join". It's really simple.Yeah, here's where you fucked up reading my post.
> anyone in any kind of role (senior to junior, technical to non-technical)
I'm talking about Joe Frontend, Billy Design Intern, Gary Office Assistant. Maybe you work on teams that are 100% neckbeards that aren't afraid to crack open an RFC to get daily shit done (and waste huge amounts of company resources on things that should be simple), but that's not the environment I'm talking about.
Not accounting for these people is the fatal mistake made by far too much of the tools and processes in software. I've watched people go into shops like this as non-technical helpers, work really hard and skillfully within the boundaries of their role, but get burned too many times by a hoity-toity technical bro "lol, you can't even open an ssh tunnel to the bastion host to connect to the internal IRC..." that they quit software, return to lower paid job they did during school and decide they have no skills, when they would thrive on a more balanced (and more socially skilled) team.
I had specifically included a scenario that is both common for use in my experience, and also pretty much impossible for a normal human using IRC in order to preempt this branch:
> Follow the directions to set it up so changes on this Trello board are posted to #channel
Sure, in extremely limited situations (so many qualifications are required here I won't list them) it's mostly easy enough for a non-technical person to manage.
Normal people (that is, people who value their own time and haven't been warped by daily interaction with software that fails to do what you asked because you failed to include some extremely implicit punctuation) laugh at many common explanations surrounding IRC, just a handful of examples: "IRC doesn't have passwords really so to prove who you are, you have to speak specific commands, like a CLI, at this bot over here, or configure your client to do that for you" "IRC has away status but nobody really uses it, because it's manual in many clients, so you typically 'ping' people and just wait to hear back if they are around" "oh yeah, if you want to get rid of all the join/part/away spam, the option for that is hidden in a menu with a bunch of other stuff, and in this client you have to set it up for each channel separately" "oh, yeah, you can't speak in that channel because you have to get the bot to +v you by direct messaging it 'shibboleth'" "btw here's the list of random-seeming letter 'flags' our server supports and how it interprets what they mean differently from other IRC daemons"
And we haven't even talked about how bad the story is around message persistence or using multiple clients or the "solution": bouncers. Getting all that going is basically a non-starter for humans unless you give in and use a service like IRCCloud that deals with search and synchronization well across platforms (but which you must be aware of in the first place).
I'm pretty technical, I've internalised the arcane knowledge, I've written IRC RFC-compliant bots to get things done (and then made them conform with common out-of RFC conventions in order to work with non-conforming IRCds), but that was all in high school, well before I gained a sense for the value of my own time. I can do it but I still refuse (to the degree that a team's use of IRC would make me pass on an offer as would I pass on a developer interviewee's inability to perceive usability problems with IRC).
I still think it'd be fairly easy to set up a company-internal server and make the whole process pretty streamlined for users. The only somewhat difficult part, then, would be the password. And I'm not sure how valuable message persistence really is, anyway, especially when you have your company email directory (and you could have IRC logs).
And for the record, I don't claim IRC's UX is without it's problems. It could certainly be improved a lot. I just don't think it's bad enough that people can't be expected to figure out how to log on and start chatting. At the same time, I think switching to a proprietary service that's run offsite is not a good solution. (We use XMPP where I work, but strangely not with conferencing. It works very well, but we're forced to use a shitty client (Cisco Jabber)). I've got high hopes that IRCv3 can start making improvements on a lot of the things you mentioned, but only time will tell.
If there were no other alternatives we could probably manage somehow, but there's much less friction in "here's the URL, sign up with your email address"
Regardless, it's not as if there aren't upwards of a dozen of off-the-shelf IRC bots you can grab off the 'net...
IRC is difficult to configure, difficult to host, difficult to use, and does not offer the same feature set as Slack. There is an obvious use case for something like Slack (obviously, because otherwise it would not have millions of users!) and covering one's ears while yelling "IRC! IRC! IRC!" is sort of wilfully ignoring that if it were a suitable solution, Slack would never have taken off.