His example was just one of many problems solved by putting stuff in space. The modern world would have a very hard time operating at the current scale of humanity without sats. Flight ops, shipping ops, transit navigation and routing for the stuff that you buy, general communication links you probably don't even know you're using when you are using them.

Slack is obviously very useful, but it's also trivially replaced. The ability to put stuff in space is not easily replaced. Conquering the inherit business risk of space operations and engineering when others won't is part the value of space companies.

Slack could be meaningfully replaced at a company with a git repo checkout and some local hardware.