Seriously, the "All Comics are Superheroes" is so common but the reality is that a large number of them are. The reason is that most writers prefer to tell stories of other genres in other mediums because comics for some reason get treated as inferior.
Maus was praised for critics, but everyone calls it a "Graphic Novel" for some reason when its just a fucking comic. The absurd of this is even worse with stuff as Sandman or Watchmen, who are outright cape stuff and still get slapped with the "Graphic Novel" tag because people are so ashamed on say they like a fucking comic.