I think the reason why a lot of companies tend to base their movies off of printed media is because of the well known IP and the fact that the already existing source material gives filmmakers a better visual of how the movies should look like in live action, while also giving audiences an easier time to get familiar and be more comfortable watching the movies. Since comics and graphic novels are more visual mediums than regularly printed books, they already have the framework of what they could do, whether it’s a comedy, action, suspense, horror, slice of life, etc.
There is a wide pool of stories and characters that filmmakers and creators can pull from when talking about comics and graphic novels, some can be very well-known like Spider-Man, X-Men, Superman, Wonder Woman, or Batman. Others were not as well-known or very obscure, like Guardians of the Galaxy, Ms. Marvel, Suicide Squad, Peacemaker, Blue Beetle, etc. And there are some indie comics that have a cult following that has grown in popularity over time like the Archie stories, or Scott Pilgrim.
