Slack is fine for many things but if I were to look during the pandemic, Teams our executed to meet people where and how they worked.
Slack is also often seen with and without context. Most people have someone pay for their slack for them to keep that precious searchable history. Non profit or free uses uses lost so much value from slack deleting their histories every 90 days unnecessarily.
Irc had bots to help.
Irc if you all me has inspired alternate experiences be it hashtags based, or a central feed like Twitter.
This is the point and the problem. It could but it hasn't. People have been waiting for it to modernize for 20 or 30 years. It took almost 30 years to add a feature people were demanding 20 years ago.
Slack etc. are poor replacements, it's true. No-one is denying that. But for all their flaws it's not hard for them to be better in aggregate when IRC is as stagnant as it is. If IRC refuses to modernise (which it has, generally) these replacements will come, whether they're good or not. I'd really like if we had something good, however we get there. But waiting for IRC to get there has not been fruitful.
"Purpose" and "fitness" change over time, while IRC has not. And proportionally speaking, nobody is. Companies use Slack and Teams, while gamers, friend groups, and a nontrivial amount of open source projects use Discord.
IRC was an instant/synchronous chat protocol. We had newsgroup/web forums for unsynychronous chat/dicussions.
The likes of slack, and later discord, had the idea of merging sync and unsync discussion to provide both.
In the end slack/discord/teams ended up being jack of all trades/master of none.
Yes the backlog is saved automatically but for most of them the search is slow and borderline unusable and it ends up being much more difficult to search for information than using google with the site:yourwebforum.example.org option.
Sorry if it comes across as snide but I really do wish it were different, I do wish IRC were less niche. But when all of its defenders start their HN comments with "I", it's difficult to see IRC supporters ever looking beyond the needs of the niche they exist in as individuals.
This is the point isn't it. If IRC were fit for purpose, we wouldn't need "modern interpretations".