re: Have wealthier whites been abandoning college football for a while now?

I've read your post 3 times now, and I have no clue if you're talking about participation in the sport itself, or in fandom.

If you're talking participation, yes there has been a decline in participation but I don't think it's limited to just wealthy white people.

If you're talking fandom, no I don't think wealthy whites have abandoned the sport. If anything, I think interest among the middle class has waned as ticket prices have drastically increased and family commitments in the fall have limited their time to commit to it.