I absolutely believe this is what happened. I think he genuinely told the people above him what it would take to keep MT (and it wasn't only money), and they told him that they wouldn't do that. Because of how disconnected from reality the group senior to him is, they were probably just as shocked about MT leaving as the press releases implied.
RG went out and tried to land a real replacement, went to the people above him and said this is what it will take to land a top tier replacement (and again it wasn't only the money), and they again told him that they wouldn't do that.
They probably lectured him about how the last AD found a dudley-do-right who managed to get to the Pac12 championship game, and they were sure he could do it too (completely ignoring the multiple losing seasons that bookended that one year). So he decided to give them what they wanted.
Enter KD.
And viola! Enter a new extension for RG, because the people above him are getting exactly what they want.
RG is getting paid to support mediocrity and failure; that's his excuse.
We don't have to pay to support that, and we shouldn't. Let Folsom become a great road trip game for visiting teams. Great location, fun trip, guaranteed win. There will be butts in seats, the AD will be in the black, and the university leadership will be happy.
Bohn was a better AD than he was given credit for. He missed on his Hawkins hire, but he recognized the need for change and reportedly was told that he couldn't do it, which led to the disastrous last year. Then a budget alumni hire was forced on him. When he was finally allowed to make another real hire, he recognized that all he had was smoking embers and hired someone who had rebuilt a program before. As soon as the trajectory was good, he bailed and got on a better train.