I really disagree. I think people learn more from failures. In many cases it seems the successful ones don't really truly know why they were successful.
Of course they did a lot of things right and it's worthwhile to listen to how they accomplished that, but if you were to duplicate exactly what they did you wouldn't necessarily be successful. So clearly there is something more to it.
In any case, there will be bad advice coming from both successes and failures. To eliminate all the "failures" as having "terrible insights" is short-sighted.
PS: I'm NOT a YC alum. And my bootstrapped company is running with revenues.
I think people learn more from success than from failure, but they learn more from failure than from doing nothing. Since typically your choice is between trying and not trying and not between succeeding and failing, your dominant strategy should be to try and let the cards fall where they may.
Aside from that, most of the people reading are in the "doing nothing" category (I'm largely in this category myself when it comes to startups, though I have tried and failed before), and so it behooves them to listen to the failures. :-)
Of course they did a lot of things right and it's worthwhile to listen to how they accomplished that, but if you were to duplicate exactly what they did you wouldn't necessarily be successful. So clearly there is something more to it.
In any case, there will be bad advice coming from both successes and failures. To eliminate all the "failures" as having "terrible insights" is short-sighted.
PS: I'm NOT a YC alum. And my bootstrapped company is running with revenues.