Where in my post does it say it isn’t? I did say when the win is assured give the bench players a chance to play.
From a coaches perspective, it is hard to instill in kids you fight every possession to the end if you begin to wave the flag of surrender when you fall behind. The very act of substituting the bench in signals to the players the hope of winning is over. That sets a terrible president for never giving up and never quit attitude.
I spent five years as an assistant to a major D1 player who coached a significantly impactful AAU team. The lessons I learned with him about never signaling to the kids that "they were in over their heads" may be the most significant lesson I have learned in life to this point. It was amazing by year five how those kids bought into the idea of never giving up, we won several games I would have said were not possible and out of reach, which is part of why I never achieved my greatest potential as a player. The idea of subbing in once the game is out of hand is death to the competitive mindset that says never give up. It also signals to the starters you doubt they can beat this team.
Most team oriented players understand their role on a team and getting better to play is done in practice or summer league out of season.
He would play the best set of five players every possession regardless of the score, and the players bought into the system.