Most culture throughout human history has been iterative instead of anthologic. Often times the stories, myths, legends, and folk tales we have are because multiple people added to the story after the original author ended it to add a piece that relates to their own time or understanding. They didn't just say, throw sunglasses and a banana hammock on Beowulf and now he's Bae-o-wulf, original character, do no steal. The story of King Arthur for example has three different origins between the changeling child, the sword in the stone, and the commoner to king stories because for the longest time King Arthur's Court started in medias res. Then there's the fact that Sir Lancelot was a later addition to the mythology of King Arthur, appearing almost six hundred years after the popular stories first appeared in public circulation as a cultural response to the rise of the idea of courtly love. And the story of Sir Gawain And The Green Knight itself was a later addition as well to epitomize the growing ideal of chivalry. Even Alfred Lord Tennyson was adding to the story over twelve hundred years after it first appeared in response to gothic literature and it's focus on the beauty in decay and nihilism. To put it one way, Lancelot, Gawain, and Elaine were essentially fanfiction to the existing mythologies that became canon.

And the truest form of that iterative culture that still exists and continues building the mythologies or characters of these stories is fan fiction. People adding onto the characters and history of the fictional world, finding what works and discarding what doesn't, and slowly weaving together a full and rich story. This is in stark contrast to anthology style works such as traditional superhero comic books, where the creators work under direction and the rules of the world and the personas of it's characters are often not allowed to change. Unlike Guinevere who is eventually swayed from Arthur into courtly love with Lancelot, Lois Lane must always love Superman for example.