Apparently since the Enlightenment this idea has gotten about that all the previous generations didn't know how to live properly, even our parents' generation; but that we somehow mysteriously know how to do it right, or at least better. But then if we have offspring, many of them might develop the same attitude towards us.

This really doesn't make sense, because incompetent people generally don't leave descendants. Our ancestors must have gotten a lot of important things right on average for us to have come into existence in the first place. Yet we think we can just reverse the wisdom of the ages in all kinds of areas and not screw things up. It looks like a kind of evolution-denialism, in fact.

How can people who say they believe in evolution also hold the conflicting idea that they know better than the principles derived from the collective evolutionary experiences of human survival?