is big money because without allegiance/loyalty it's not that great of a product to generate billions(just look at every other sport in this country that's not the best league in the world).

Being fair weather and just switching teams doesn't carry the same investment and emotion, bad or good.

Now as far as kids go, switching loyalties based on who they become alumni for is usually what happens and makes perfect sense. Maybe they go to a school without an FBS football team and just never really become loyal to any school and they choose different entertainment in their lives like you said with skiing/biking