Playing time

I have been to all the 5th grade games so far this year and last year and have friends with boys who play football. Well at least they get to suit up and play maybe one series. These boys practice hard 4 times a week and they rarely get to play in the games while other boys get to play offense and defense for most of the game. How is this very motivational? Some of these kids would like to play for years to come. How is this helping them learn gameplay when they stand on the sidelines game after game. Also, do you might think the boys who are playing so much get tired and that's why they lost the game on Saturday? Just a thought. Thank you.