The modern tendency of schools with big stadiums (90,000+) is not to add more capacity in the form of high endzone upper decks, but to add more revenue producing skyboxes and club seating on the sidelines. Some schools, like Oregon, have actually reduced capacity by 20,000 or 30,000.
LSU recently had the option of building endzone upper decks which could have eventually raised capacity to almost 120,000, but they decided instead to demolish the west sideline upper deck that was only 20 years old to replace it with a bigger sideline deck with three levels of club seating to match the two levels of skyboxes on the east side. It only added about 600 seats to capacity, but the revenue it produces is huge with 2,500 club seats that bring in $2,800 per seat every year in surcharges.
The problem with high-level endzone seats is that they are just too far from the field and have a poor view. Many folks just aren't willing to pay surcharges for such seats and the endzone upper decks never pay for themselves. With almost every game on TV these days, many fans who can't get seats close to the field, will choose to watch it on the bigscreen. Even schools who regularly sell out every game have a problem with many no-show empty seats in the upper end zones, especially in a bad year. Nobody likes seeing empty seats. And AD's don't like additions that can't pay for themselves.
