Dear Miss Snark --
Okay, so I've gripped the basic concept that agents who handle book publishing projects don't usually also handle film rights. I don't understand why a book agent's initial contract with an author would include a clause that gives them a generous % of the film rights on a novel [say 10%] even though they don't handle film rights. Is that just a perk for the book agent or are they going to do a lot of work to earn it? If the author says -- this is all about books, let's either write a contract that includes your Hollywood subagent as a signing party, if there ever is one, or just leave the film rights you don't handle out of it -- would the book agent call her a snooty diva and give her the boot?
You never worked as a waitress or a bartender did you?
The people who couple 'generous' with "10%" are usually the ones who order the 16 ingrediant drink, the dressing on the side, and complain their gazpacho is cold.
If you think making a film deal is just a matter of sending your book off to Hollywoodland on the Sunset Limited, and your book agent isn't going to be doing quite a bit of work you are heading in the right direction: LaLaLand.
When prospective clients start quizzing me about why I get a percentage of a film deal, I take it as a sign that they don't understand the business very well, and they really don't understand that there's a lot of work they will never see, and a lot of work that never bears fruit. If I wanted to rob you blind I'd charge you by the billable hour, ask for a reading fee, and enroll you in the Killer Yapp Charm School.
And film agents aren't teamed with literary agents. It's entirely common for a literary agent to work with several different film agents on different projects.