That trend is going to continue for some time, and the advent of cheap HDTV is the cause. An 85" TV costs like $700. The view is better on TV than in person, you get up close replays, the beer is cheaper (and colder), you can invite the same friends to your living room that you'd invite to the game but they don't have to use a porta-john while they pregame. Oh, and the wifi is better so you can TikTok your reactions to big plays in real time.
College football is just as popular as it ever was, but stadiums are just big TV studios now. That's why all the money is tied to the TV contracts and not in-person attendance.