A portion of a TVG interview with Adam Kahn, Senior PR Manager at LucasArts...

TVG: As you mentioned earlier, there's no multiplayer in the game. Was there any specific reason for this?

AK: To be specific, there's no multiplayer in the Xbox 360 and PlayStation 3 versions, because there is on the Wii, PSP, and DS. As far as specific reasons are concerned, we don't really like to get into the reasons why we don't do things because I don't think there's really a satisfactory answer that people would really be happy with. So, there isn't multiplayer and that's kind of how it is...

Wow, isn't that answer a bit...curt? We didn't put it in because we just didn't, next question. I bet someone wish they had the Jedi Mind Trick ability. "You don't want to know anything about multiplayer." (wave of hand)

Full interview here