I'm genuinely curious how you hold someone accountable that makes more money than you do, or whose contract is longer than yours or is a franchise/star or fan favorite player or otherwise holds some type of power over you.
I can see a capable coach or mentor motivating a player to excel for various reasons, but holding someone accountable whose position is equal to or higher than yours would be a tall order.
There are players you can't bench, can't fine or otherwise discipline. A demotion on the depth chart coupled with reduced playing time will affect your next contract, etc. That may apply to older and more mature players who have been in the league longer as they are maybe looking to their next contract. This could also lead to a player who is more concerned about injury than he is in excelling. People are who they are, whether by birth, environment or the luck of the draw. I think it takes maturity, if you aren't born with it, for a person to realize they have additional potential... Then again, you can't really make people do anything. They either do it, don't or land somewhere in the middle. You can't make anyone care. You can beg, plead, cajole, threaten etc but being a mentor/leader to others requires ability, dedication and a willingness on the part of both participants. I remember myself in my early 20s and young people now in my life, most of us weren't capable of looking beyond the end of our nose. Imo, you are either born with it or mature into it. I'm guessing a good coach can guide people to mature into it, but in my experience, most people won't leave their comfort zone of their own accord.