My dad tells me that baseball was all he ever thought about when he was growing up. I played every sport growing up but stayed with baseball even though football was my favorite sport but my mom taught high school and really discouraged me from playing because of the players she saw were beaten up so badly. Probably not a smart thing to say on a sports wagering site but that's the way it was.
I think part of the reason we like it is the same reason my mom hated it. It is a rough and tough sport and action packed. Factor in a 4 month regular season in the NFL and 3 1/2 for college and the anticipation builds up. I tried NBA fantasy once and with games every night almost, it made it hard to stay motivated. Less product, more demand.
Sum it up for me:
Shorter season, more interest. A little more than 2 games a week for 4 months. Other major sports go on for 8 months with daily games.
$, pure and simple. Network and advertising dollars flow freely
wagering and fantasy football.
The physical nature of busting heads. Something innate and hard to explain.