in High School, a coach cannot afford Not to have his best athletes on the field at all times. Offense, Defense, returning kicks....gotta get the ball into the playmaker's hands at any cost.
and No, there aren't always enough players, depending on the situation. High schools can't (legally) recruit.
If we fight for money, I will stop hitting you when you ask me to.
If we fight for honor, I will stop hitting you when I feel like it.