I went to OU for undergrad and have kept up my contacts pretty well over the years. I don't have the inside connections now I once had, but still have a few contacts.
I know Bob was not pushed aside. No chance of that.
Bob had the longest tenure of any coach in FCS (Snyder has been at K State longer, but took a break for several years), and it is the first time in history a school had the same president, same AD, and same football head coach for that long a period. The policy of the suits at OU basically was give Bob anything he wants.
My guess is that it was a combination of health issues--his father died of a heart attack at age 54 while coaching on the sidelines, heart problems run in his family, and he has had a heart condition himself the last few years which has been controlled by medication--and a desire to have some time to watch his twin sons play their final year of high school football.
The unrelenting pressure a head coach at an elite program is not a good combination with a heart condition.
He is only 56, but both OU coaching legends, Bud Wilkinson and Barry Switzer, were done by that age (Barry was pushed out) and even hall of fame coaches like Darryl Royal and Frank Broyles retired younger than 56.
Bob has amazing success--a bowl game every year he coached, more conference titles than home losses during the 18 years, more 10-win seasons than any coach during that period, won national title and played for several others--but there was still a lot of grumbling from fans the last few years.
Fans never gave him the type love they showed Bud and Barry, and Bob disliked having to spend time with fans almost as much as he did dealing with the press. I've seen him blow up several times when faced with softball questions from fans on the publicity tours OU puts on in various cities where there are big alum concentrations.
It won't come as a total shock if he coaches again--he's a football lifer from a family of coaches--but I will be surprised if he gives the pros a shot. The state media that fawns on the Sooners is a picnic compared to a big city, and he gets pissed even having to deal with softball questions.
A lot of rumors he is interested in the Bears job--based on the fact he owns two semi-mansions in Chicago--but he would probably have a heart attack during a press conference if he took that job.
I think Mixon played at least a small part. It wasn't just the original punch, Mixon had several other explosions, including threatening a meter maid, tearing up a ticket and throwing it in her face, and driving his car towards her until she got between two cars. Bob has taken high quality kids for the great majority of his signings, but has taken a few chances and most of them blew up on him.
Also, OU is not as good a job as it was when he took it. If OU ever lost a top Texas recruit it was usually to Texas. Those two schools had their pick of talent. Now it is hard for OU to get even one top recruit out of Texas. When aTm went to the SEC it changed recruiting forever. The Aggies and other SEC teams now all dip into Texas talent and Ohio State always signs one or two a year.
Even Oklahoma is not locked up anymore. For decades OU almost never lost a top Oklahoma player, but now that has changed as well.
My guess is Bob has had enough. He is rich enough to never need money again, and any time you are taking drugs so powerful they can control some heart function you know you better make things as easy on your body as you can.