They didn’t use to fight. I mean, they hit each other and screamed epithets at the Road Crew and drove luxury cars into one another, but they didn’t fight fight. There were drunken arguments that escalated to Billy trying to curbstomp Bobby (true, pg. 110) and sometimes it came down to pistols at dawn, but nothing simmered.
Things were different back then, though. Everyone didn’t have their own team of managers and lawyers and Benjy Eisens telling them how much more important he was than everyone else.
Everything changes; nothing lasts.
Also, Billy’s hair looks like Neil Diamond’s 80’s bouffant wig had sex with a werewolf.