Wow I had no idea this was taking place. It reminds me a little of the fight hollywood screenwriters have fought to get equal billing and recognition. I always assumed that the writer got the most money!
Maybe in Christopher Nolan's case that may be true. Even in the rare case of an original script i doubt that the writers get any significant slice of the pie. It would be interesting to know more about how the film industry pays its contributors.
They also have very prominent credits, second only to the director (notice it's the second to last in opening credits or second if it's closing credits).
Their biggest issue is all the unpaid work they get asked to do. They can do months and even years of work without any compensation with projects that aren't really moving forward.