Not so much an "upstart like Slack", more like "a giant pool of upstarts, the best of which happens to be Slack." When looking at it like this, it's easy to see

Not so much an "upstart like Slack", more like "a giant pool of upstarts, the best of which happens to be Slack." When looking at it like this, it's easy to see why Microsoft and Google (or any big company for that matter) has trouble competing.