It's pure conjecture, but his time puts in and worries in certain areas probably lesson when hiring all of these proven coaches. It probably makes his life more relaxing just letting these type of coaches just do their jobs and he can focus on some other things....less micromanaging. That's sheer conjecture obviously.
The old saying, "I you wanna be an Eagle you gotta soar with Eagles!". In other words, you gotta surround yourself with quality hires to reach the pinnacle.