I agree completely.

But we're talking about reasons people ended up choosing slack over something like IRC (or, really, any open protocol instant messaging specification).

The grand-parent comment raises good points, people want these things, being connected and reachable while not being connected to the server with any client and having a context later on. These are problems that can be solved but nobody has put effort into making a sexy product to do it. (and monetising that kind of product might be troublesome)

> nobody has put effort into making a sexy product

Again we are comparing a product to a protocol.

I’m just pointing out that this is not a reasonable comparison.

There were multiple web-enabled IRC bouncers (closed products) which would be easy to use for anyone, including non-techsavy people.

But evidently the majority of IRC-users were fine without that and preferred the traditional client-server-protocol realm.

IRC is more than a protocol, it’s an ecosystem. You cannot simply talk about IRC in complete isolation.

It’s akin to comparing SMTP with chrome.

You have to include the clients and surrounding infrastructure.

Yes, and there was plenty of opportunity for someone to develop a client that scratches all of those itches. But they didn't.