These games are a "Made for TV Extravaganza!" People in the stands are nice and all, but unnecessary. For We The Fans, it is a gargantuan expanse that cannot be easily repeated, so even if one chooses to attend a game there's little chance to attend a second because few people have that kind of money laying around.
Mrs. Brewingfrog and I were watching one of the "Playoff" games a few years ago, and the ESPN commentators were complaining about the Alabama fans "not filling the stadium" like they were expected to. Mrs. Brewingfrog snarled at the TV, "Well, they've been to the Playoff like three times now, and played in five games, and each of those games cost a ton to go to! Alabama fans are tapped out! They've spent what they can! Do these idiots think that we're just saps who will empty our wallets when they tell us to?"
Why spend the money when you can watch it on TV?