I mean, this looks like if you're heading to every single away game, and let's be honest, how many fans does any NFL team have that make it to all 20 games (assuming there's no postseason, even)? It's got to number in the hundreds or low thousands at best.
I am heading to London for the Cards game, and I do have to make the trip down and back for every home game, so it is expensive overall, but I mitigate the costs by flying Southwest, and putting all of my large bills (utilities, cellphone, etc.) on their credit card, so I generally have enough points to fly free. Throw in a USAA rental car discount or hopping in the car with a buddy once I land, and all in all, it's not overwhelmingly expensive.
I'm sure once the Raiders move here, it'll cost more than it does for me to go to Cards games.