STID is by no means bombing or flopping, it's just not doing the buisness Paramount hoped for. I think there was a moment there after the 2009 film where people got carried away and thought with the right director, budget, explosions and sex appeal that Trek can be traditional summer blockbuster and move out of the Thanksgiving or Christmas releases of past Trek movies.
Well yes and no. Trek can compete in the summer blockbuster arena and put up very solid, respectable numbers, but it can't do what Iron Man or Star Wars does and just break open the bank. The international box office will always be higher b/c overseas audiences aren't nowhere near as fickle and trendy as North American movie goers are.
The nerd/dork/loser stigma associated with the Star Trek franchise is just way, way, WAAAY too srong. There are many people out there that just won't give a Trek movie a chance no matter how many action stunts, A-list stars and sex you put in it. The franchise should actually be damn proud of itself that despite the stigma it actually competes very respectablly in the summer.