I think declining attendance at college football games is due to television. The game has sold out for television money and this has two negative effects.
First, the experience watching at home is much more comfortable and enjoyable. Many people, old and young, prefer that experience especially when the weather gets dicey.
Second, the television timeouts and other clock stoppages create an unbearable stadium experience. The experience is even worse when the team is below average and the weather is bad.
Maybe I'm getting old, but the MSU game this year got me thinking about splitting my season ticket up with someone, or buying single game seats for a few games a year. I can stand being in the cold, and even watching a mediocre team, but I feel like such a sucker sitting through those 4 minute TV timeouts.