I'll live up to British stereotypes and say this is form of behaviour strikes me as being rather unsporting. Yes there will be competition between manga and comic books but you don't need to bad-mouth the opposition. And besides, super hero comics and manga do have a lot in common as they share virtually the same consumer base. This is why polarising the nerd market i would argue is actually bad for the comic book industry in the long-run, as it would discourage manga consumers from buying comics. If comics presented themselves as complimentary to manga rather than opposed, you'll have a lot more manga fans trying out comics.
Or, DC Comics could branch out from making purely super-hero comics. Forced to choose between manga or comics, i'd go for the former because manga has such a wider scope than American comics do. You could read romance manga's, sci-fi, fantasy, comedy, horror, thriller etc....you can get manga's about anything. American comics tend to restrict themselves to the world of super-hero's- they keep to just one genre. Frankly i'm surprised the super-hero franchise has lasted so long. Genres appeal to certain times, and superhero's developed in the context of WW2, a time when the world needed super-hero's. It's only be it's devout fanbase which has kept the thing alive.
It's impressive and almost surprising how super-hero's have managed to break successfully into the world of cinema. Probably because film studio's were amicable to nerd culture with the success of LOTR and Harry Potter- plus, things like LOTR and super-hero movies just invite fancy CGI at a time when special effects were undergoing a sort of revolution- for the first time you could film something purely fanciful and it won't look like an old Dr Who alien, it will look real. This is why the first 3D film blockbuster was a sci-fi film, and Superhero's filled this demand for fancy CGI beautifully. But this super-hero renaissance won't last forever, CGI will cease to be a new and fantastic thing- like colour television, and we'll take it for granted. Then the world of super-hero's will return to the twilight, niche minority interest it is destined to be unless comic books don't expand into more general genres.
I don't mind the genre of super-hero's- I happily watched Captain America, and the Dark Knight's an excellent film. But the vast majority of cinema-goers who watched those films didn't go out and buy comic books, me included. Part of the reason is, as MovieBob may acknowledge, is because the genre is so deep and complex with so much back story it makes getting into that world and understanding it very difficult. But also, i'd wager, it's a bit of a one-horse race, people like different genres which examine different themes and different topics- it captures a wider audience, and that's why manga is more successful than American comics because manga captures pretty much every conceivable genre imaginable.
