Survivorship bias. For every success you describe there are nine or so failures. Skill being involved doesn’t exclude being lucky, and I believe being lucky (some people call it timing) is of utmost importance.
But it doesn't make the survivors wrong about their experience. Two truths: their experience did happen roughly how they said it happened + they got very lucky.
Seems like all the other 9 that died insist on telling the one that survived that they were somehow wrong.
For sure, I do get that one can "do everything right" and still fail, I get that point, I get that there is no formula. But it seems like people want the reverse to be true: that everyone successful is only a lucky buffoon.
Ya, I respect this view. It is not the view I have, but I understand how you can have it. Eg, this is how I feel about most famous portfolio managers. Really my comment is addressed to the other view -- if it _isn't_ luck, then I think we should put some weight in what the successful practitioners say, and the ones I've heard do endorse the lean startup & co.