Yeah, I started somewhere around 6-7 Slack communities. I use exactly zero of them anymore. I still feel guilty for roping multiple communities into the service and helping multiple group of people have somewhere to hang out, only for the rug to get pulled out from under all of us.
I once even went to a doctor and the staff was using Slack because it integrated with some calendar thing they had.
This is 100% gone.
Fancy startups are still using Slack but in two I worked at, they migrated to Teams or Google after a while, as soon as they were acquired.