After vito genevese benny squint lombardo was the boss and he was grooming gigante as his protege.
Why was he the chosen one? What did he do that made Genovese and Lombardo think so highly of him? The only thing we know that he did was botch a hit and go to prison for dealing drugs. That's not exactly a great resume.
He was close to older men like Genovese who ran things, and outlived them. It seems no one challenged him for the boss position, so he got it.
