Here's the problem with a guy like Thamel jumping to conclusions based on the "Alliance" statement that the conferences aren't expanding and the Big 12 is going to be on the outside looking in. In addition to being some hardcore confirmation bias, his scenario he expects doesn't solve the two massive problems that absolutely will and must come to a head soon. That is the terrible ACC deal and the dire financial situation of the PAC. He just says, this all sounds like these will be the power conferences and the Big 12 will be left out, and here's a scheduling alliance.
First, the PAC 12 absolutely must do something or they are as good as dead. The Big 10 can commit to not poaching the top of the PAC, but it does nothing to solve their financial problem. This scheduling does very little, if anything. USC, Oregon, and to an extent Washington and UCLA get big non-con games as it is. Maybe it helps a bit in the mid-tier teams, but we're talking about minimal impact on a per team basis.
Second, and probably more importantly, the ACC (or at least the top teams in the conference) absolutely have to get out of their terrible media deal. Basically they need to have whatever level of change occur that will allow them to get out of that deal. It's a financial disaster. Not that ACC teams need to match the SEC or Big 10, but Clemson isn't going to live with getting 1/4 of the money or so of a bunch of these SEC teams.
So Thamel can say, nobody's expanding, they're just doing this alliance, but that's pretty idiotic. Two of the three alliance conferences are in deep **** and are unstable. And there's nothing in this alliance that provides any stability or a fix for the PAC and ACCs incredible financial disadvantage. The PAC and ACC need some extent of organized chaos to reset their media deals within a couple of years, or they are going to be as good as dead.