I think we things are a changin. As many on here have stated the stadium is filled with less than young adults. IE Blue Hairs, man I wish I had blue hair or some, nevermind. I have talked with friends that have made the comment, that the trip to the stadium is harder every year, watching on TV may be easier for them. But on the same note, my grandfather went every weekend until he was into his 90's.
Internet, Big screen TV's, far more games to watch from the comfort of the easy chair. I know I have missed USC games due to the fact that other games were on and I wanted to watch them. I am not a die hard SC fan, and know I would never miss a Nebraska game if I could walk. New knees now, so that is not a problem!!!! Getting old sucks guys, and damn it there is no escaping it. Trust me I have tried!!
Being The only game in town/state makes it better for Nebraska. Most have grown up going to or dreaming about going to the Big Red party. I think we are safe for awhile, but down the road in your kids senior years it will change. The old stadium will have to come down, new facilities, better people access, possibly more comfortable seatS and larger for their larger butts. But I would not worry about Nebraska not selling out in your lifetimes, as long as we keep winning and improving.