$4 in 2002 is equivalent to $6-7 with the US treasuries own inflation calculator; but I never really argued that, I argued their current cost.
Other than that it is obvious to me that you’re out of touch with reality entirely. $12 per user per month for a chat tool is a legitimately unjustifiable amount for the majority of the current slack user base.
You can argue that free is freeloading, perhaps I agree, but saying anyone not forking over €12/user is not a serious user is just insanely dismissive to the point of absurdity.
You also completely missed the point: BBSs were a one stop shop for all the features and more that slack has, IRC was the same but lacked persistence, which was bolted on, XMPP also had all the features slack had and is being sold to you as things like google talk and Facebook messenger (which is XMPP underneath!).
Slack innovates in marketing, telling people that they want this stuff. The product is not innovative and for the average/prosumer user the value simply isn’t there.
Zulip is so superior it is actually disgusting; and it’s FOSS.
Not to mention “matrix” or the multitude of fantastic walled garden chat tools.
Slack enjoys a niche because of rugpulling, bringing people in with marketing and UX and the promise that you can work with your existing client and cheaply so don’t worry about it! (IRC/XMPP gateways; generous free tier) before removing them.
That you defend this makes me believe you have a financial incentive.