1/3 of the conference is new and from G5 (yes, they are good programs). I have mentioned this before, but the only thing that makes the big 12 stable is the fact that none of his schools are being targeted for expansion. So you have a fairly new conference that hasn’t played a single game together, has lost more teams than any other conference in current existence, Just lost their two biggest brands, doesn’t have any flagship programs, and very few of your alumni live within the footprint of the conference.
There are probably other reasons, but these are just a few of them. I don’t think this is the last phase of expansion. I think that the SEC and B1G are going to expand until they decide they are done and then you are going to have those two conferences and everything that is left over of quality will band together.
So I don’t think people look at the big 12 as an area of stability in terms of past or future outlook. Why not stay with an organization you know and people that you have worked with previously? You have clout and a say in things. You have an easier path to the playoffs with fewer teams.
With all of that said, the pac12 has been such a mess. I wouldn’t blame anyone for leaving. I just don’t think teams like the big 12 enough.