Slack is today's version of a modern accessible IRC client.
It doesn't preclude from the issues of slack being solved by another group.
edit: For the IRC uninitiated who enjoy drive-by downvoting: Slack is IRC-inspired - the concept of channels, usernames, private messaging and bots.... in slack is almost all directly inherited from IRC.
I'm not sure why everyone is downvoting this. To repeat myself from another thread: give people generous readings. Slack isn't literally a modern accessible IRC client, no, but it's "today's version," i.e., today's equivalent. Slack is absolutely IRC-inspired, and services like IRCCloud[1] suggest that it'd be possible to build most of what Slack "adds" to IRC on top of IRC's existing protocols.
In a lot of ways, I think Slack's biggest advantage has just been ease of use in modern times: you don't need to know anything about downloading a client and configuring it -- even the friendliest IRC clients I've found are still pretty fiddly compared to "enter your team name, your email address, and your password, boom, done." But this seems like it'd be a relatively easy problem to solve.
And it never was an IRC client, there was just a somewhat limited bridge you could use to connect your IRC client into Slack network, but never vice-versa.
Besides taking my comment literally (I now have clarified), lets look at it from a higher level:
The concept of channels, usernames, private messaging in Slack is almost all directly inherited from IRC. There is some great new functionality on top of this core, IRC inspired experience.
It doesn't preclude from the issues of slack being solved by another group.
edit: For the IRC uninitiated who enjoy drive-by downvoting: Slack is IRC-inspired - the concept of channels, usernames, private messaging and bots.... in slack is almost all directly inherited from IRC.