Because stories are important.
People think that stories are shaped by people. In fact, it's the other way around.
Stories exist independently of their players. If you know that, the knowledge is power.
Stories, great flapping ribbons of shaped space-time, have been blowing and uncoiling around the universe since the beginning of time. And they have evolved. The weakest have died and the strongest have survived and they have grown fat on the retelling . . . stories, twisting and blowing through the darkness.
And their very existence overlays a faint but insistent pattern on the chaos that is history. Stories etch grooves deep enough for people to follow in the same way that water follows certain paths down a mountainside. And every time fresh actors tread the path of the story, the groove runs deeper.
This is called the theory of narrative causality and it means that a story, once started, takes a shape. It picks up all the vibrations of all the other workings of that story that have ever been.
This is why history keeps on repeating all the time.
So a thousand heroes have stolen fire from the gods.A thousand wolves have eaten grandmother, a thousand princesses have been kissed. A million unknowing actors have moved, unknowing, through the pathways of story.
It is now impossible for the third and youngest son of any king, if he should embark on a quest which has so far claimed his older brothers, not to succeed.
Stories don't care who takes part in them. All that matters is that the story gets told.
Witches Abroad by Terry Pratchett