This essay from Aeon makes the observation that folktales weren't always about fighting for a noble value. Rather they were just about getting what you want, without framing actions in a strong moral light:

Stories from an oral tradition never have anything like a modern good guy or bad guy in them, despite their reputation for being moralising. In stories such as Jack and the Beanstalk or Sleeping Beauty, just who is the good guy? Jack is the protagonist we’re meant to root for, yet he has no ethical justification for stealing the giant’s things. Does Sleeping Beauty care about goodness? Does anyone fight crime? Even tales that can be made to seem like they are about good versus evil, such as the story of Cinderella, do not hinge on so simple a moral dichotomy. In traditional oral versions, Cinderella merely needs to be beautiful to make the story work. In the Three Little Pigs, neither pigs nor wolf deploy tactics that the other side wouldn’t stoop to. It’s just a question of who gets dinner first, not good versus evil.

The situation is more complex in epics such as The Iliad, which does have two ‘teams’, as well as characters who wrestle with moral meanings. But the teams don’t represent the clash of two sets of values in the same way that modern good guys and bad guys do. Neither Achilles nor Hector stands for values that the other side cannot abide, nor are they fighting to protect the world from the other team. They don’t symbolise anything but themselves and, though they talk about war often, they never cite their values as the reason to fight the good fight. The ostensibly moral face-off between good and evil is a recent invention that evolved in concert with modern nationalism – and, ultimately, it gives voice to a political vision not an ethical one.

Greek mythology also tended not to hinge on so simple a moral dichotomy. Zeus and Hera’s rocky relationship is literally legendary, yet in all of the stories involving their marriage the audience isn’t pushed to root for one or the other. Zues is a philanderer, and Hera is jealous and vain. When Zues fell in love with Calisto, Hera turned her into a bear. When Hera lost the competition as to who was “the fairest goddess" (to Aphrodite), she started a war to punish the judge, who happened to be Paris of Troy.

These legends don’t rile moral passions like the classic Sith-Jedi, Voldemort-Harry, and Hook-Peter Pan nemeses do, but they are a more accurate portrait of life. The world is made up of people with sometimes (but not always!) competing intentions, which come down to truly difficult tradeoffs rather than a clearcut “good" vs “evil". It’s more a question of how we want to spend limited resources/prestige than about intentionally destroying or saving everything. (It’s a shame really—everything would be a lot simpler if the bad things in the world were that clear cut.)

Ancient stories tend to be more agnostic as to who wins, while modern stories tend to force you to pick a side. And usually there’s really not much of a choice.

The Aeon posts post argues that this is because the good-evil dichotomy is a useful political tool, which make sense, but it leaves me with a question: why did people only start using that tool relatively recently? Maybe it’s just a technological and scientific improvement like anything else, a technique that took time to develop. Maybe the ancient Greeks and Germanic tribes just didn’t have a good enough grasp on human psychology to recognize its power.