Then I think you're ignoring the empty seats near the end of most of our home games. It's natural to take for granted what we have right now (not justifying that attitude - just being realistic). Almost every year since 2009, Alabama has been a part of the CFP or NCG. IMO, fanbase wealth has little to do with this - I think that its just fans (including me some years) taking for granted the idea that "I can always make it to the next one".
More to the point though.... the average starting salaries from both schools are almost the same, and we have 70% more students. Income is not the issue.
https://www.usnews.com/best-colleges/compare?xwalk_id=217882&xwalk_id=100751
Edit: And I don't mean that to sound like I'm slamming Alabama fans or students at all - just reiterating that I think the biggest factor is that our opponents have not been in the same position as us (or at least as long as us) - so yes, they typically are more willing and excited to turn out in droves for these big games.