>>128161593Firstly, the audience for comics is measured in thousands. What we like isn't necessarily what everyone else will like. When you're introducing Marvel characters to the masses for the first time via a cartoon or a movie, they don't know or care which ones are "the popular ones" in the comics, they're going to decide for themselves who they like.
Secondly, Marvel's plan was doing separate cartoons for each of the solo-book Avengers characters, and an Avengers cartoon with the other core Avengers characters (minus Quicksilver, but plus Falcon, Wonder Man and Tigra), with potentially four lines of merchandise to go with them. They made an Iron Man cartoon first, and an Avengers one, but Captain America didn't make it out of development, and they never even started work on a Thor one. The kids this Avengers cartoon was aimed at didn't even know it and Spider-Man Unlimited even existed, because they scheduled them against Pokemon at the height of it's popularity.