I think that while it is possible that they will start looking at anime and manga, that the returns will be at a lower level and that the culture at large and the genre fans won't embrace these adaptations quite as they have the American super heroes, though outside the U.S. the BO could well be quite good.
For one, Superman, Batman, Spider-Man, X-Men, and yes even the Avengers characters like Iron Man, Thor and Captain America, they were ingrained in American Pop Culture long before they were big hits on the screen. Some are even transcendent of films in their own way. Certainly Batman, Superman and Spider-Man are. Not to mention these characters are being adapted from American source material by Americans.
Anime and Manga creations are relatively new to the Pop Culture landscape in the states, at least to the degree they have been so recently as compared to the days of Robotech, Voltron ect. The crop of serious "hits" (arbitrarily let's say "serious" means your Death Notes, Berserks, Bleach, Attack On Titans, Evangelions, and so forth. The series made to be viewed in and of themselves and not just advertising a game or toy or the like, so this is discounting Yu-Gih-Oh, Pokeman, Digimon, and their ilk) on these shores is still pretty niche, though the youth market does tend to have very loyal fan bases that are starting to matriculate into more important demographics... Still, the Anime/Manga fandom is wider than it is deep I'd say. The other thing is... These would be Americans adapting something from Japan. The term "Lost In Translation" comes to mind. Hell, it comes to mind anyway with the way Anime/Manga is already consumed in the States. Some idioms, cultural references and tropes just don't convert well, if at all. This is a double edged sword. Keep them as intact as possible and you risk making a lot of the audience scratching their heads. Replace or ignore those elements and the hard core fan base which is important in placating will feel betrayed. I think there is more latitude with the Marvel/DC stuff, surprisingly, than there is with Manga and Anime. SO much IS tied to Japanese specific stuff, I am not sure how to thread that needle.
Now... In adapting Anime/Manga the starting points of many franchises and stories is incredibly intriguing. Conceptually most are very sound, but I think INO type adaptations are what would work for live action films, not the sort of things Marvel Studios is doing with it's properties, where sure, liberties are taken but in the end they remain pretty faithful to a lot of aspects. I am not sure Anime/Manga would be given that level of care in adapting, with good reasons as I already stated. And again... We are still dealing with a niche thing.
Of course all it takes is one or two films to crack the code and we may well find lots of adaptations coming down the pike afterwards. There is also the world wide BO to consider, so if in trying to squeeze more out of South Asian markets Hollywood sees a good shot with Anime/Manga, we may well get these adaptations sooner than later.
