I can buy into this. At some point, even if the hitting coaches have little to no impact, you cycle in a new one just for the sake of doing it and infusing a new energy. That said, I do also believe there is value in consistency within the staff. Team that cycle in a new manager year after year, new systems, new approaches, new philosophies - I think that can be detrimental in many cases (this probably applies more in football with their "systems", but I still do think it applies to baseball).
I would also like to hope at in the "bro" culture, the players would also look at each other and hold themselves accountable. In my experience, coaches/managers can preach all they want, but teams really come together when they hold each other accountable for their actions. If someone's out getting loaded every night, or someone is spending the offseason crushing cheetos, coming to camp out of shape - the players need to speak up and tell them that's unacceptable and hurting the teams chances for success.