That's not the say that it's impossible. Look at what exposure due to the TV show has done for the Walking Dead. There's a definite tread upward that has accelerated since the show has been on the air.
Their best shot at getting new readers is the movies in addition to TV and games. I don't know how you can fault a business for trying. If they don't get new readers, the number of current readers will eventually diminish by attrition.