After effects of the hurricane are not the primary reason. Nor is it preponderantly about losinmg over the past couple of years. Following an 11 win season, fan support was lackluster. Fedora simply does not inspire fans, does not keep their passion aflame.
I don't care for Fedora, but I do not believe that Larry Fedora's presence is what keeps people away from home football games. I don't think he HELPS to improve the situation. But, I also don't think the lack of butts in the seats is some protest against Larry Fedora.
UNC just doesn't have a fervent football fan base. Or, not as fervent as what you see at places like Clemson. It never really has had one that I ever saw. The last 10-20 years have really taken a toll. It also depends on the game. Look at the NC State game from 2012 and Gio's return for a TD. It was bulging that day.
Between Bunting, all of the NCAA crap going back to Marvin Austin, and then the AFAM crap, and Butch getting canned, and Fedora's failures, it's just been a buzzkill. Aside from 2015, it's been mediocre on its best day, with a few really shiny spots (the Gio game, for example).
I really believe that the basketball culture, and UNC fans used to winning so much, makes fans lack enthusiasm when you compare the lackluster football records.
I also think they enlarged that stadium way too much BEFORE they had a product on the field.