Is it a foregone conclusion that everyone ultimately wants to be a head coach?
Guy is from Buffalo, has 6 kids and a family, could get a new contract with job security, loves Josh and the team. McBean and this ownership group is as stable as it gets for him. For those with a young family, thats important.
Hes already got the perfect job. Not everyone wants to risk moving their family to a new city for a job with a potentially high failure/turnover rate. Not everyone wants the headache of managing a team/head coach responsibility. If the guy loves offense and football, he might be destined to stay a coordinator and thats fine.