"Doubt kills more dreams than failure...but Random Chance is like, Grim Reaper for dreams."
Success in startups (and life in general) is not the linear function that most of us want it to be. It isn't related in direct proportion to the amount of effort, intelligence, work, time, love, energy, etc that's invested. It's more of a logarithmic function. There is a minimum amount of effort and those other things that must be put in to have any chance of success. But after that the returns diminish rapidly. It's comforting to think that if we just try harder or smarter we can triumph in the end. But the fickle winds of fate have the ultimate say, and any sense of control is probably an illusion.
Saying that a company failed due to lack of product-market fit is like saying that a sports team lost due to not scoring enough points. It's always a true statement, but it doesn't illuminate the cause of the failure in a way that would be instructive to others. Most startups that were successful enough to be included on this list probably did 80% of things "right". Some times "it just didn't work out" is all that you'll be able to say.
Despite all that, I think there is a lot of value in these autopsies. Being able to learn something, anything, from the experience of others is very valuable. Knowing more about what causes failure won't guarantee success, but it sure as hell beats knowing nothing.