I’m not sure the exact point at which souther football caught up to and surpassed the north, but I think northern fans were moving on long before that, and much of it had to do with divorcing the sport from any serious connection to academics. That is certainly why the Ivy League decided to get out of major college football.
In 1973, when Bear Bryant was trying to earn respect for the south, football superiority was still up for grabs. He only lost to Notre Dame by one point, a bitter loss for regional pride at the time, and that as a kid almost made me cry, but a sign things were changing. Alabama finally won in 1987 after four tries. Notre Dame’s fortunes will always be limited in our new reality due to scruples about academics.
But, again, southern football, in particular, seems to be clinging to a tradition that other parts of the country don’t share. When I lived in the northeast I never saw anyone invested in personal validation by beating some team from some other region, at least not the fans I knew. That is as southern as grits and hush puppies.