My high school humanities teacher referred to this as the "Crazy archetype cycle." You start with a golden age of peace and paradise, there's a fall and a release of sin into the world, an age of evil, a cataclysmic extinction event, a slow return to a near-golden age, and the whole thing starts all over. A culture's myths tell you a lot about where in that cycle it perceives itself to be. Which is a really interesting way to look at popular media; comics certainly seem to think we're in a golden age, between the valorization inherent to the superhero genre and the obsessive concern of GRIMDARK comics with the inevitable fall.
It's more, I think, that we're in Dark Times, but a new Golden Age is coming, though we have to work for it. That's one of the themes of the Perez run; the world's gone to hell, and Diana is sent to teach people how to fix it and make it a better place.
What has been Batman's main concept since Miller's Year One is, again, the world has gone to hell, and the Dark Knight's quest is to protect the innocent and, again, make things better.
"To show them the way." That sums up the superhero myth, and the purpose of Myth in general, I think. The old stories are supposed to teach us. Tolkien thought modern writers needed to create new myths to serve the purpose for our modern culture that the classic myths did for the old ones, using the classic archetypes that are deeply built into us.