I read a book about literary criticism some years ago and one of the points that was made is that there is the “one big story.” And every book or movie is just a retelling of that one big story. Which is why it should be no surprise that you can take two very different books or movies and the same themes reverberate throughout. Essentially telling the same story with different characters.
For instance Ferngully and Pocahontas is just a retelling of Romeo and Juliet or Antony and Cleopatra, which is a retelling Solomon and Sheba or Adam or Eve.