See that actually bothered me because how does the Sorcerer have any influence in our world? He mentioned Walt, but then also “a man who watched shadows on a wall” is very clearly Plato and then there were “playwrights” It actually sounds like every Author was from our world….
I think there are multiple Authors. One for each realm. It just so happens that the Author for the Enchanted Forest decided to influence the outcome of his realm by nudging people along to do what he thought would make a good story.
We know that the Sorcerer at least has some ability in our world because he sent Ingrid to the Land without Magic and gave her the scroll to enter Storybrooke.