Sales of comics have almost nothing to do with the visibility of the property in other media.
Iron Man sales are strong not because of the movie, but because it's tied in strongly with the rest of the Marvel Universe (such as Dark Reign and now Fear Itself) and because it's some of Matt Fraction's best writing.
Likewise Thor is because of the new #1 and Olivier Coipel. Captain America also because of the relaunch and because of artist Steve McNiven.
It's very simple. Television and movie viewers simply do not translate into more comic book readers. It may once have, but that is in the past.