Screenwriting : Branded Material by Carlos de La Torre

It's been a while now that Big Studios favor financing High Budget scripts that are based only on Branded Material. So if you've written a High Concept story you're better off writing a Book that becomes a best seller before you can expect a big time Producer to consider your script.....I understand. But what if the theme behind your story is as well known or even more popular than most of all Branded scripts now days? Wouldn't this factor make your story somehow Semi-Branded? Hahahaha! Let me give you all an example. Let's just say your theme for your stories is "World Peace" but behind the plot of your stories you have very well known Mythological characters highly involved with your theme...then, what if you feel you don't need to write books about your stories cause after all these are Mythological Branded characters recognized by everyone in the world? Wouldn't this be considered an exception when someone tells you: You should write a book before you submit your screenplay... I mean: Do Big Studios believe when it comes to financing that the only way to secure a large audience is by banking on a Best Seller?