I think the P5 or nothing is an opinion driven by jealousy.
Those 5 leagues were around years ago, and the system was even more rigged then, and BYU fans still packed the house. It doesn't matter what we do conference wise, BYU fans will still show up as a group even if some iindividuals come and go.
I'm typically not interested in watching BYU games in November. You're currently watching those games. If BYU joins a conference then that flips and it's a net neutral for BYU. I think support is the same in either situation, I'm just saying for me, I prefer conference play.