This is the least surprising news ever.
The trailers don't explain why the character or story is unique. I don't even think most people know it's on Mars or that he's from Earth and is basically a superhero due to the lessened gravity, instead he just looks like a guy on a planet with some aliens and some normal human looking types that should all be able to do the same kinds of stuff he does (I know this isn't the case, but that's because of people online who like the books and League of Extraordinary Gentlemen, not anything in the trailers). I don't know anything about The Hunger Games, I've never read a book, but the trailer spells it all out. It's a girl in a terrible future where random kids are picked to fight to the death to get food for their area. Her sister is picked, and she steps up to volunteer to take her place. She then trains, and eventually has to fight in a show that's broadcast all over the world/country, along with a love interest. If I'm wrong, feel free to point it out, but that is the basic plot as far as the trailer is concerned and is way way closer to the plot than anything from the John Carter trailers.
The title is horrible and generic. Saying they cut "Of Mars" or "And The Princess of Mars" to try to appeal to a wider audience is just ridiculously stupid, even if it's true.
The action just looks OK for the most part. There's really nothing that stands out as amazing.
Since the character is not well known by most people under 50, there's no familiarity with the characters to add in a level of "wow I can't wait to see how they do ______" like you get from The Hobbit or The Avengers or The Hunger Games or Twilight or any adaptation really. The Prometheus trailer is nothing but cool looking moments that evoke an iconic trailer to a really popular movie. Batman has Batman. This one has some alien dog thing and a giant monkey monster.
It has no big name stars to attract people, and despite Stanton doing great stuff on the Pixar cartoons, he's far from a household name and isn't capable of being a huge draw yet.
And then they went and spent way way way way way way way too much on it anyways. I can't see any way, even if it does OK, that it isn't considered a huge bomb. It would have to be The Dark Knight or Avatar to turn a significant profit. If it's Iron Man, it's still nothing. If it's the first Twilight it's a bomb.
It's entirely possible it's a really fun movie and that it later becomes somewhat popular on DVD, but the marketing has been awful, some old people with a passion and access to a checkbook way overestimated the public's desire for this to exist, and despite the fact things like Star Wars ripped ideas from here, it's coming so far after the fact it looks like the one ripping off ideas. I'm sure there's some older people that will love this movie and that have waited decades to see it, but it's not shocking at all that it's not resonating with most of the general public.