Johnson and Parcells are probably the worst examples anyone could choose. Johnson hadn't won anything in the NFL before he arrived. Jimmy got him two SBs and still they couldn't coexist. Jerry couldn't stand the idea of sharing credit or the spotlight with Johnson. So much for credibility -- "clout and authority."
Parcells lasted four seasons. Jerry forced Terrell Owens down is his throat when Parcells wanted no part of TO. When they agreed to an amicable divorce, Jerry summarized his position by saying, "I'm just not having fun anymore." So much for credibility -- "clout and authority."