If the American comic book market ever implodes it will be because of its terrible business model. Manga is just better on so many levels...
1. It’s built around creator and publication loyalty rather then character loyalty. DragonBall was and still is very popular but Shueisha (Shonen Jump’s publisher) isn’t going to collapse if they stop publishing it. DC would disintegrate overnight if they had to stop publishing Batman or Superman. Manga readers seem to be more loyal to creators, publications and genres then they are to characters.
2. Manga is cheap. American comics are to expensive for what they are.
3. American comics are to difficult to get into.
4. American comics are to reliant on the big two, and the big two are to reliant on Superheroes.
5. American comic adaptions are to different from the comics they are based on.
I feel American comics need a radical transformation in business model, and I think it might take either on of the big two going down or some external force( most innovation comes from outside a particular industry) for it to happen.