Earlier quoted context omitted.
Not that it'd be easy but I imagine that you can steal their customers by adding chat rooms and integrations slowly to some other type of software, rather than a more direct angle where you have to win at one of those two moments.
Microsoft Teams with their decent video conferencing might have an angle plus being “free” part of 365.
So my view is that until Microsoft get their act together, Teams is not a serious contender to Slack. Companies can get it "free" together with their Office subscription, but most developers won't use it until it works decently on their development platform of choice.