Marvel has brought a new meaning to the word "A-lister", the lines are sort of blurred. Rocket Racoon was a "D-lister" five years ago, now I see him everywhere. Is he now an "A-lister" like Superman, Batman, and Spider-man? In my personal opinion those are the characters with the most sustained popularity and significance, so almost nothing else touches it. Now Captain America, iron man, Thor, star-lord, rocket raccoon, are everywhere. It's debatable that they, for the moment, have just as much cultural significance as the aforementioned A-listers.
Obviously it's a different story when you talk about the comics. The Fantastic Four are deeply significant to the Marvel universe in the comics, A-listers no doubt, yet their cultural significance is absolutely laughable.