Almost everyone predicted when Bud retired Wiles would go too. Many possible reasons on both sides. Not sure if true, but some indicated he had choice and decided to go.
Understandable when you are 55 and have worked for same boss for 23 years that might not want to stick around and work for
Guy 18 years your jr. Who played for you.

Certianly if Wiles had wanted DC job and JH got instead would be hard to stay.

On the other side, yes Wiles has been good recruiter but DL recruiting has been down. Recruiting is mostly a young man's game. At 55 perhaps Wiles energy and effort on recruiting trail has waned as well. Would not be unusual or suprising.
Who knows if he is going to return in some lesser staff role as analyst, might be exactly what suited him at 55.

Maybe he was given choice you can stay but these are the expectations and standards I want met in terms of commitment to recruiting in terms of time and travel and Charlie said no thanks, I am 55 toward end of career not willing to work that hard, etc.