Yes but however, due to all the integrations everywhere, their retention rate must be incredible.
I cannot imagine that any medium company would invest the time and money necessary to quit slack. Especially when you have bots everywhere.
It’s not that it’s undoable but you have to replace it with something reeeeaaaally awesome to justify the pain.
Today Slack is pretty meh, there may be better alternatives considering your use case but nothing so awesome that you would do it.