It probably hasn't helped the film (which I haven't seen) that it was released in September, a traditional dumping ground for movies the studios have little confidence in. On top of that, the reviews were fair
, but not great. On top of that, as noted, the film doesn't have any major stars (Karl Urban, although he has been in several high profile releases, hasn't been the star of anything successful as far as I know) and wasn't especially well-promoted.
I'm not sure I buy the backlash against 3D argument, although I would be happy if it were true.