Originally Posted by
90'sCartoonMan
Mark Millar can write a comic book mini-series as though it's the pitch for a live action adaptation. I'm sure that's what he has in mind most of the time (whereas the more famous works of Frank Miller and Alan Moore came out so long ago, adapting them was unthinkable at the time). Gaiman's a different animal, it's mostly his books (like Coraline, American Gods, or Good Omens) that fit more for the screen as opposed to his comic book work. Despite his name recognition, something like Sandman is a tough beast to pull off, and in this current environment, it would have to go through a ton of changes (if something like Lucifer is any indication).
Morrison has the same problem, he likes out there metatexual genre-bending ideas made specifically for comic books. Seaguy, WE3, stuff like that are incredibly off the wall. That isn't to say he can't do something more grounded (relatively speaking) like Happy! he just doesn't have a history of churning out books ready to go like Mark Millar.