I don't think this New Yorker essay, by Michael Chabon, gets to the heart of what makes comic books so captivating to boys in quite the way it so obviously aspires to do, but it does have some wonderfully precise observation, particularly this little tour-de-force on the fashion "etiology of the superhero costume"
making due reference, say, to professional-wrestling and circus attire of the early twentieth century, to the boots-cloak-and-tights ensembles worn by swashbucklers and cavaliers in stage plays and Hollywood films, to contemporary men’s athletic wear, with its unitard construction and belted trunks, to the designs of Alex Raymond and Hal Foster and the amazing pulp-magazine cover artist Frank R. Paul. I could cite the influence of Art Deco and Streamline Moderne aesthetics, with their roots in fantasies of power, speed, and flight, or posit the costume as a kind of fashion alter ego of the heavy, boxy profile of men’s clothing at the time.
I'm not enough of a design historian to say whether this etiology is right or not, but it sounds right.
On a side note, I was, it should almost go without saying, once a comic book reader of great voraciousness and lack of discrimination.