People have to travel as a result of business or a need to get from Point A to Point B in less than a week.
People don't have to go to NFL games, and frankly, having been to a few, I don't really see the attraction in going to the stadium when the coverage on television is much better, and free.
I used to go fairly regularly (at least once a year) to see a NFL game live. The attraction was that it was "just us guys" time, originally between my dad and I, and then later, between my son and I. It started out that Dad would buy the tickets to a game that the two of us could go and enjoy together (usually whenever Oakland came into town). Then, when I got old enough to be out on my own, and had a bit of my own disposable income, I'd buy the tickets, and treat dad to the game.
Nowadays, dad's been dead for 4 years now, and my son is just as happy going with me to the local college games. I pay faaar less money than I otherwise might at a NFL game, get better seats (usually first row on the 50) and don't have to worry about my 7-year old getting groped by a perv with a badge and a gun. Yup. I really have no incentive to watch a game live anymore.