its not like they tell the kids to pick up their comics.....first of all, the kids who watch the movies dont go pick up the comics, they pick up the toys and games, which is understandable seeing as they like it and they want one
batman and superman wouldnt be household names without sales obviously, so at one point kids were doing the same thing "wow, i wanna get superman and batman toys!!" not to mention the billions of toys for their cartoons, JLA, the batman, and teen titans
DC isnt some magical company that gives things out for free, they do the exact same sh*t marvel does, so theres no point in saying "marvel makes advertisements to sell things!!!" of course they do, EVERYTHING DOES
did the hellboy movie do good? yes, did it boost their comic book rating? not by much, did they sell toys like crazy? yes
people wanna make those movies because they're interested in those characters or stories, no one makes a movie out of characters they dont want or a story they absolutely hate
so of course jugg74's point is accurate, but not only for marvel, for the entire business industry