Look, a lot of rounds of financing — all the way to a Series H —at almost any valuation do add up to significant dilution:
Beyond that, Slack took additional dilution from its pivot from a gaming company to the Slack we know today, a communications company. They sold 25% to Accel (and more to other investors) before the tilt … so in a way, they took 30%+ dilution before Slack became Slack.
I find that dilution picks you in many ways. Each company has a different path. Different types of competition, different market dynamics, different amounts of virality, etc. Both founders will shortly be phenomenally wealthy, and more importantly, I think more wealthy that they even needed to be.
The last company they co-founded together, Flickr? They sold it for $40m. Even with all the dilution, they will make 250x more on Slack than Flickr. Maybe much more than that. So it’s all good.
And finally, as a side note to other founders, Stewart was granted more long-term options/shares as CEO later. This is fairly common when a founder CEO does an amazing job, stays on (doesn’t bring on an outside CEO), and is substantially diluted. The VCs often give the CEO more shares (with a new, longer vesting period). More on that here: 5 Interesting Learnings From Slack. As It Gets Ready to IPO. | SaaStr
and more here: MoreSaaStr.com