Would you, though? My company was a very early user of Slack, and imported our history from Skype group chat, IRC and HipChat over various periods in history. You can get the data out of Slack easily enough, so I don’t see that as a major aspect of lock-in if there is a competitive product.
The integration story is more interesting, but to _be_ a competitive product many of these must already exist.
The job of competing with Slack is harder than it once was (just look at MS Teams) but not impossible (just look at Slack...) - there’s lots of room for improvement.