NCJacket, you know there are exceptions to just about every thing. I can tell you from personal experience that the older you get the quick decisions do not materialize as fast as they did when I was younger.
When I was younger, I could glance to the side of the road to admire a beauty walking down the road. If I try to do that today, I am already in the ditch when I have looked back to the road. The reaction time in my mind seems the same to me, but it is evident there is a greater delay in time.
Yes there are exceptions and some can still overcome the aging process of the mind and reactions, but as a whole it is better to have someone who can react quickly to the situations and the kids.
You will understand better when you begin to reach the elderly status. That is really why many elderly coaches start losing their edge and more games.
If I was a head coach, I would prefer my assistants in the mid twenties to mid thirty range. I would begin to watch them more closely after that range to monitor their relationships between themselves and the young athletes (age gaps).
I would want my OC or DC to be in the late twenties or early thirties to about the age of 50. I would monitor their timely decisions more closely nearing the age of 50.
If I was the AD, I would want my head coach to be in the early thirties (if he is very talented) up to about the mid fifties. After the mid fifties, I would expect the head coach to be turning a lot of the control of the team over to the OC and DC and become more of a mentor than a hands-on coach.
After the mid-fifties, I would keep a close eye on the head coach, his relationship with the OC/DC, and his record. If his record started dropping after that age, I would be making a list of future candidates for the job while keeping a close eye on his continuing abilities to make proper and timely decisions.
Of course, only my opinion, but age does play a roll in quick decisions.