At the end of the day, the first tier of costumed crime fighters is limited to just three members -- Superman, Spiderman, and Batman -- truly ubiquitous figures who any American could recognize even if they don't know anything about them.
Iron Man belongs firmly to a second-tier of major comic book characters who'd be instantly familiar to anyone who was, at any time in his or (less likely) her life a reader of superhero books.
Where a lot of folks surprised about the success of the Iron Man film seem to me to have gone wrong is just in underestimating how big the audience for the second-tier is.
I can buy that. Surveying Iron Man's success and then recalling the box office success of second and even third tier properties such as Ghost Rider, Daredevil, Hellboy, and the Fantastic Four, I've been wondering if comic books are so ingrained in the culture that "superhero comic book" movie has become a bankable genre all on its own?
The number of total flops from this genre is pretty small: League of Extraordinary Gentleman, Catwoman, Elektra, and The Punisher, and that's about it.
But maybe this is really just about what Yglesias sees--a huge, acceptance of and appetite for second-tier comic book heroes, so long as the movies are somewhat competently made.
*One small quibble with Yglesias: I think the first-tier could reasonably be widened to include Wonder-Woman, the Hulk, and maybe even Captain America, all of whom occupy an enormous chunk of the popular consciousness.