Maybe Louisville is in the mix to keep football from becoming too much of a meat grinder. If you start combining a bunch of schools into a single conference that all think of themselves as national contenders, and then they start to get squeezed out of their spot in the pecking order, people get unhappy and instability starts to pop up again. Just look at Nebraska. They were getting pushed to second tier status and walked away from a century of tradition without giving it much thought.
I think that could be true with some schools, but here is what I think about...I currently live in Arkansas and have asked many people, would you rather be a consistent 2-4th place finisher in the Big 12 with some championships mixed in, or traditionally a lower half SEC team (which is what they've been the last 20 years until recently). Every time they say we'd rather play in the SEC and be a bottom feeder than be up there with Texas and OU every year competing for B12 championships.
I used to live in Texas and had a number of A&M friends. Same thing. They'd rather be a SEC bottom feeder or average joe than be a consistent #2-3 B12 team and compete for a few B12 championships.
I would think the logical fan would rather be a big fish in a medium pond than a medium fish in a big pond. Why would someone want to see their team pushed to "second-tier" status as you say? I agree with you, but I think the emotions of envy (Nebraska), fear (Mizzou), and anger (A&M) that drive realignment overtake logical thought.