Maybe because he is the main character and the best one??? Trevor is a f*cking prick and Franklin just stands there all the time, he's not even making part of the main thing, Michael and Trevor's story
I love Micheal but I really am getting sick of this, there is NO main character, there is a main cast, a main group. All 3 of them are highly important to the story, is Franklin a little in the background? Yes, because he hasn't DONE this stuff before, he doesn't have the past relations Micheal and Trevor has, these are 2 people he just met and stuff he is doing for the first time.
Oh and being a prick does NOT mean they can't be a main character.