I am playing devil’s advocate on this, so keep that in mind as I respond to your questions.
Does he have any evidence to show that these relationships and research partnerships would NOT have happened if not for the jump to the P12? In other words, is the P12 relationship the driving factor or is it that the vast majority of R1/AAU accredited universities that are in the Western part of the US are in the P12?
Does he account for any non-obvious confounding variables, such as a change in the priority from university leadership towards research funding?
The short answer is no, there is not significant evidence to support causation. It‘s a podcast, not a peer reviewed academic paper.
The longer answer is that both CU and Utah had a major bump in research funding after joining the pac 12. Perhaps both just had a leadership push toward that goal, although I think it would be safe to say that all leadership of major universities are making the same push. He also shows, somewhat tangentially, that other schools that moved into the Big 12 did not have the same bounce. And existing Big 12 schools had no bump at all. In fact CU and Utah’s bump was in many cases almost equal to the entire R&D for many of the Big 12 schools. So, it did not appear to be a “rising tide lifts all boats” scenario. It appeared that CU and Utah got a bump unlike others. And joining the PAC 12 was one common denominator. I have no idea if his figures are correct, and there absolutely could be other factors in play.
I found his arguments to be generally logical. He was essentially trying to answer the question, would any PAC 12 school go to the Big 12? Based on research funding, alumni reach, the rotten Big 12 grant of rights, the academic prestige, and the actual dollars involved, he made a credible argument that no school would leave over $5 million per year because everything else is a downgrade.