just call me this, but you could write up all this on failed young coaches as well. It's still all a gamble and young coaches need to be able to find the right QB to fit their systems or they will be out the league.
Hey there Debbie! You can do the research to write up something on failed young coaches if you want. My post emphasized the turnover ratio of NFL Head Coaches and the trend of 1st Time Head Coaches being under 45 years old and most having an Offensive background. I know it's a long read but that may summarize it a bit.
I'm not so sure about a coach coming in and finding the right QB to fit their system. In most cases there is already a QB in the building and if not, you're drafting one to be the Franchise QB of the future. In either case the player may not fit the system that a coach would like to implement, and it would be best to build a system around the player until you acquire a player that fits the system you prefer to run. The old adage of not trying to fit a square peg in a round hole applies.