Things around the program were hopping up until around 2015. In the 2013-14 academic year, if I'm looking at the seasons correctly, we were going to our 3rd of 4 straight Nola Bowls, went dancing, baseball had its historic season and softball went to the WCWS. A cajuns ticket was the hottest thing in town. Don't know if it has anything to do with it, but RCAF's first executive director was hired in 2015 according to the site. Going straight off of memory here, that's when they started trying to monetize everything and the downturn started. I'm 38 and A LOT of people that I grew up with were at lots of games for lots of different sports up until then.
For me personally, my first of 4 was born in 2014 and kids are expensive. Choices were made and that's why I watch a lot of games on ESPN+ now. Timing, overpriced product and convenience were big factors for me and I'd assume the same applies to a lot of people my age.