I think people have had enough bromance to last the rest of this generation. When Nathan Drake and Commander Shepard are getting with the girlies, who wants to play a game where your only partner is a dude?
Seriously though, I think it just got lost in the shuffle. Modern Warfare 2 is still fresh in people's minds, Mass Effect 2 just dropped, and we've got a ton of better games to spend $60 on.