Hero emulation is the predominant strategy in younger ages, whilst at the older ages, a few others are added to the tableau, such as
1) promise of education. These boys are actually given "scholarships" (sic).
2) promise of a way out of economic deprivation (great career)
3) anticipation of groupie adulation, and even intimate relations.
Some see football as a way to develop oneself mentally, physically, and spiritually. Sometimes that works, I have known a few lost souls who found their way in sports, including football.
Some see football as the right thing to do, the thing that will let them "defend" their communities "honor" (school, city, community, etc).
Notice the Military uses many of the same strategies (Be all you can be; Stop Communism in its tracks; Army Proud; The xxxxx needs a few good men; Only the best) Over the years I have noticed a gender difference in a couple of things, girls want to look nice, or at least presentably. Boys (read men) want to be dominating, physically superior, and be around "heroes". So recruiting strategies work on these characteristics, for better or worse.