Earlier quoted context omitted.
If you want to be bold, start your Slack replacement now. Do whatever you can to make it easy to transition to your product (API compatibility, integration compatibility, etc.). Be ready to pick up the people who will be disgruntled by Slack in two or three years. You may never be as big as Slack but there's probably a business there.
There probably is but it’s really hard to compete with a company with deep pockets. That’s what I find pretty worrying about these unicorns. They kill a lot of potentially good smaller businesses just by being able to burn a lot of money.
gitlab and bitbucket ain't github, but as github started burning, they started picking up steam. github sold for $7.5 billion. If they can get 1% of that value, that's still $75 million. If they can do so on the cheap, maintaining control, that's not a bad return. I doubt something like gitlab requires more than 5 people to do well enough to achieve that, given patient, low-overhead investors. Done well, that's $75 million returns for a $10 million investment. If you toss the investor $50 mil, and each employee $5 mil, it's not bad.
On the other hand, as far as I know, patient low-overhead investors are a myth.