Failure, in this context could either mean product or company failure, and the "fail fast" adage is usually applied to product, not company. At least as this article presents the story (executive churn, etc), it sounds like company failure is the main part of it. The issue with "unicorn" failures is that a product can be really successful in objective terms (users, revenue, profit..) but still an investment failure,…
IIRC he bought it from the investors for cheap (so they could get it off their books) and then just ran it as one guy (maybe a few more added part time later)... and it does just fine in that conext, and who knows what might happen from there.
Kinda makes me think that a lot of Unicorn style world domination or nothing, result in some business opportunities being lost if those are the only two options.