Loved the NFL when I was a kid, and you could follow a team (and the players) for 9-10 years.
Niners...with Montana, Rice, Lott, Michael Carter, Randy Cross, Harris Barton, Roger Craig, John Taylor, Tom Rathman, etc.
But then:
1) Free agency made it difficult to "bond" with a team. The players change every 2-3 years.
2) I went to college and became a college football fanatic. The stadium atmosphere is incredible, the gameday atmosphere is incredible. Nothing beats a college night game. You start tailgating @ 8am, and everybody is CRAZY by 7pm.
When I think of NFL fans, I think of guys watching the game on their sofa. They've got some chips, beer, soda, etc. They consider this dedication.
When I think of college fans, I think of guys spending hundreds (thousands?) of dollars on tailgate equipment, just so they can enjoy several hours on campus before the big game. And don't forget, lots of them drive 4-5 hours just to attend the game.
I went to a Ravens game a few years ago, and they played crowd-noise over the speakers. Pathetic.