That's the hell of the thing, as the article points out: you'll never know what you screwed up.
Yes, it'd be great if you could have 100 people all starting from the same point and everybody learning the lessons of what worked and what didn't because of total openness, but that's just not happening. Instead you'll get 2 or 3 survivors writing blog articles about how awesome their startup is without actually reporting anything at the level of detail you'd need to actually improve.
This would obviously only work if you had an inherent advantage in the market though haha.