There are so many reasons John Carter was a "flop".

- Definitely shortening the title to something so generic sounding was a strange idea. It doesn't sound like what the story is.

- The film was put together by Burroughs fan boys who seemed not to realize how few other Burroughs fan boys there were out there. It needed to work harder to get the interest of people unfamiliar with the material.

- Besides those two, the marketing generally failed this film. It could have performed a lot better if Disney had handled it better.

- While there was a lot of eye-candy on the screen, the art direction lacked a strong overall unifying vision. It needed more of a "look", the way "Alien" had a look.

- The box office wasn't all that bad for a film that didn't expect to be a blockbuster. But too many people involved were too confident that it would be a blockbuster. It wouldn't have failed so hard if they had been able to bring it together for less money. Part of this was over-confidence in how easily the director of wildly popular animated films would make the transition to live-action. They're different.

- While the character actors were great and the leads did fine, with that kind of budget you need a star who fills seats. I don't like this fact, but it's a very real part of the movie money game. Either spend a lot less money, or spend a bigger percentage of it on a star.

So, it was a flop by Hollywood standard, but that's a financial judgement. I thought the film was good, maybe good enough for those already fans of the material, but it missed a lot of opportunities to be much better. If there could have been a scrappy lower budget intro to the franchise, that might have opened the way for sequels, but that's not what studios like Disney are fond of funding.