I guess if the point is to find out How long it took different companies to find product-market fit (title of the submission) you could argue that failed startups never found it?
I agree with OP - lots of survivorship bias here. To be fair to the author - going through the heaps of companies that didn't make it would be a sig more work.
Most likely the failed companies didn't find it but possibly were close or other issues sank the company. Curious actually if there are companies that found product market fit and didn't survive. That's an interesting group.
Most likely the failed companies didn't find it but possibly were close or other issues sank the company. Curious actually if there are companies that found product market fit and didn't survive. That's an interesting group.