#1 - Independent schedule hasn't produced many quality home games in terms of opponents.
#2 - Prices did go up the last few years, some who could barely afford tickets in the past simply are not doing so now. And No, a one or two time price reduction for a game won't instantly bring those fans back.
#3 - Moving long time ticket holders from their seats (Ie.. South endzone) can tick these fans off, therefore they stay home.
#4 - TV - everygame is on the tube now, just have to have ESPN to get it in HD.
#5 - Long term consequences of BYU attendence and academic policies, instituted in 1989-1990. A lot more local kids end up going to UVU, Utah, Utah State and have little reason to cheer for BYU.
#6 - Death.. yep.. fewer blue hairs and they are dissapearing sadly everyday.