Slack and Teams are not the same, Slack is a communications app, not a collaboration app.

I know how to use Teams properly, and I have entire departments (government, universities, etc) that I have trained to use it and they get mad every time their IT departments try to introduce a new product that Teams (and M365) already handle just fine.

Mom and Dad didn't do their fucking research before buying it and didn't bother to read the fucking manual after they did buy it.

Don't tell me the average user is correct when I get called into help offices multiple times a year that are still using Excel sheets to manage their vacation requests, manage their tasks on a blackboard on the wall of the office (even though they're half remote), build their HR forms in Adobe, and have network drives with 90,000 files in 20,000 folders where nobody can find anything all while already owning M365 licenses.

People aren't using Teams' integrated collaboration features properly, and it's not because they're worse than their existing processes and they have some sort of magic ultra-efficient system already, it's because they simply do not know how to use them properly.