Why, do you think? Age, apathy due to UT's mediocrity, changes in the sport, all of the above? Most of those have hit me, too, but I still love it. I'll still watch meaningless games on TV, especially early in every season, and I will watch all of the playoff games this year if I can.
I really haven't given it much thought. But, since you prompted introspection,.... I don't think it's age at all, except that I have relatively young children who take up more of my time. And, I lived through the mediocrity of the mid/late 70s with a passion for the game, so I doubt that's it. In fact, I am more excited about Coach Jones than I ever was about Coach Majors. The truth is, I am still passionate about the Vols; I just do not enjoy watching them on TV, so I quit doing it a few years ago. It's much better for my emotional wellbeing.
I also still enjoy and "get into" the games when I am there live, but I still have a better time at the tailgate with family and friends. I
LOVE that aspect of Vols football, and I have even gotten reacquainted with a couple old high school friends over the past couple seasons.
As for other teams/games, I just don't enjoy watching on TV for more than a couple plays. I'm just not interested (no reason to care). I do enjoy going to games live, but that's seldom an option. I guess it all boils down to there being more important things in life to occupy my time, so I am treating it that way.