IRC does not solve half of the problems all of these products do. Persistence, for starters.
What kind of persistence are you talking about? I use ZNC, which means I'm always logged in (and set /away when I'm not actually there), and I get logs saved to disk.
Slack offers an IRC and XMPP gateway, I think HipChat does as well.
What happened in April 1997? Isn't that a long time post-IRC?
I had the date wrong.
I think you're still late; a quick look suggests August 1988 is the date you're looking for?
Last time I looked into it, security was not a big emphasis for the IRC protocol in general [1], and setting up your own IRC server and finding high-quality open-source/free clients was more trouble than it is worth.