So says this article, echoing sentiments I've heard elsewhere lately. What garbage.
First of all, since when have superhero movies relied on "manly men" for their stars? Was Christopher Reeve oozing with machismo? Michael Keaton? And while we're at it, would anyone describe Ryan Reynolds and Andrew Garfield as "manly?" Though comic books themselves tend to "roid up" everyone in them, superheroes aren't necessarily "manly" types. See Spiderman, for example, who's a nerdy college student by day. Superman's alter ego has to pass for a mousy reporter, and Superman himself conforms to a World War II era vision of masculinity that's quite different from our own.
Meanwhile, two of the most "manly" superhero leads I can think of off the top of my head are Punisher and Hellboy. That's Thomas Jane (Baltimore, MD), and Ron Perlman (NYC). Perhaps one could add Wild West-style comic book hero Jonah Hex to the list, and thus Josh Brolin (Los Angeles, CA). Yes, Wolverine should be included as well, but there are plenty of Americans here holding their own against Hugh Jackman.
It's not like there aren't still a shitload of Yanks playing leading/manly superhero roles. Possibly the biggest superhero movies of the last 10 years this side of The Dark Knight was Iron Man. That's Robert Downey, Jr. (NYC). Then there's the last three Spiderman movies (Tobey Maguire -- Santa Monica, CA), Ghost Rider (Nicholas Cage -- Long Beach, CA), Kick Ass (Nick Cage again), Blade: Trinity (Wesley Snipes -- Orlando, FL), the Fantastic Four movies (Chris Evans -- Sudbury, MA, Michael Chiklis -- Lowell, MA, and Doug Jones -- Indianapolis, IN), and the list goes on.
One could perhaps make the case that Brits and Australians are still overrepresented in superhero movies, but that's because they are so in all movies. Remember all the talk about the Australian invasion of Hollywood a few years back with Eric Bana, Russell Crowe, Naomi Watts, Hugh Jackman, etc.? The British, meanwhile, have always done pretty well for themselves in Hollywood. Canadians, too.