Wow.... so complicated!
IMO, everyone has their own vision of their perfect band. Finding 3 or more guys with the same vision is almost impossible. Too many things have to click into place. Genre, attitude, work ethic, look, class, egos, age, values, ability, business sense... the list is endless. Being a band leader is like herding ADD cats. Most bands try the democratic thing, which makes it almost impossible to get everyone on the same page.
True, you will run into people with personality disorders, but I think they get weeded out pretty quick. If everyone believes their vision is the proper direction of their band, and they all disagree, and none are willing to compromise, which one has the personality disorder?