That doesn't solve the problem of name registration, file/picture sharing, group membership/moderation, customization/emoji, planning, etc. that are handled easily with something like Facebook Messenger groups. IRC is super clunky by comparison.
I pay for IRCCloud, but the problem is that it only fixes everything for you. It does you almost no good when nobody else can receive a message after they close their laptop or go through a tunnel.
The IRC communities speak for themselves. Pretty much all regulars, no new blood, tiny, and opinionated grouches that are kinda hard to stand. You'd think #javascript or #node.js on Freenode would be pretty big. Nah, I'm on there every day and it's about 10 regulars. I could list off the usernames off the top of my head.
To put that in perspective, my Slack community for people who like building MUDs has more regulars and it's hard for me to think of a smaller niche. If you're trying to set up a community and you think IRC is good enough and you refuse to offer alternatives, your stubbornness is only disserving your users and community.
I can think of many more options too, like how Elm's IRC channel makes you think nobody uses the language, yet Elm's Slack community is thriving and more fun to participate in than #javascript and #node.js, and is far more popular.
Ease of use is definitely a big factor. It would be interesting to see if it were possible to try to build a community using IRCCloud first and basically use it as "Slack but with an irc gateway that will never go away". Their free tier modalities seem a bit too restrictive to allow that though.
That used to be the story. I used to offer a Mibbit gateway to my IRC community that got a lot of use 10 years ago.
But today, it's a hard sell. IRCCloud doesn't compete on features against alternatives services, it's strictly worse since it has less to work with.
When a user adds your community, it gets added to a list of all their other servers on Slack/Discord. The question has become "so why are you making us use this instead of setting up a Slack/Discord/etc server like everyone else?"
And I think you'll be hard pressed to answer them in a satisfying way. And for no real gain.
There are other groups who heavily use these features. We've got over a thousand custom emojis in my Slack at work. Our interactions would be just slightly less rich without :badpokerface:, :sadpanda:, or :superhero:.
For some reason these IRC vs X discussions always have the IRC party attributing character flaws to everyone else.
Like not being creative enough to read the same amount of information from ":)" and specific, rich, custom emoji like, I don't know, someone simply shrugging. That's some bizarre self-aggrandizement.
I encourage you to go on a Twitch channel and tell me the :) equivalent of all the custom Twitch/channel images you see in chat.
And that's fine. None of us want to take IRC away from you. And it's fine as well for you to advocate for IRC, so new people can find out about it and join it. Some of us like other chat services though, for various reasons, and we enjoy using emoji in playful ways and to supplement the lack of body language in written communication.