Hey, my wife and I are 60 plus, and we always come away hoarse after a game in the shoe. Heck, we sit in D deck and we know there is no way our voices will be heard on the field, but we scream none the less. Now I must admit I am a little shy about standing because I'm 6'5" and standing will block those behind me even if they are standing, but I'm on my feet quite a bit.
The real problem is the season ticket process. Priority is given to large donors so you get quite a few of the cheese and wine crowd around and the stadium. It has more to do with the corporate $ than the age of the patron. When your entire marketing effort for seats in the stadium is centered around those corporate accts, that is what you will get. I spent one game with a 40 something woman seated next to me. She spent the whole game texting and taking selfies to show she was at the game. I kept having to explain to her what happened on the field. She was not an alum, just married to a guy (not an alum either) who can donate big bucks to the university so he can get ticket priority.
FWIW, most of those corporate seats are empty by the end of the game. We slways stay to see the entire game and sing Carmen at the end. Very few corporate fans do so, in fact many start leaving by the end of the 3rd qtr.