When all the departures started, those three guys certainly got input from elsewhere, but they were the primary decision makers about whether OU would stay in the conference or move on. Other coaches got to contribute, but if that time period taught us anything, it was that football is the real consideration. It was why KU, despite an unsurpassed basketball environment, found themselves on the outside looking in when other conferences came asking.
There were a lot of supplemental decisions. Stay with Texas? Stay with OSU. Would there be state legislature intervention for or against any particular decisions? But it was told by more than one insider that Bob was asked for his preference, specifically about going to the SEC and he was against it. It was likely the number one reason why OU stayed in the XII. This was a multi level decision. It had to be made when Nebraska and Colorado left. It had to be made again when Mizzou and A&M left. And again once since.
If OU wanted to be in the SEC, it would already have happened. I'd be very shocked if that move were made while any of the those three are still in OU leadership. And if Joe C or President Boren were to retire, then I'd expect Bob would soon follow. But that's just a hunch on the latter. But if both were to move on, I don't think Bob would stay much longer. Might even see all three go at the same time. But those guys are going to keep us where we are in all likelihood.
Most of your post regarding the three is just a hunch on your part. You know nothing more than the average fan. I admit I have no idea. None of us know.