I guess my point is that Dave Culley should not be written off simply because of his age and having never been anything more than a position coach.
As I said, who knows what kind of coach Culley becomes. But, searching for first year head coaches that mirror his age and coaching experience is a challenge. Tom Coughlin was 49 when he got the Jags job. And he had been a college HC for 3 years prior.
Gunther Cunningham received his first and only NFL HC gig at 53 with Kansas City. Cunningham had been an NFL assistant for 14 years before getting the Chiefs top job, the previous 6 years as the KC DC.
Marv Levy became a first time NFL HC at 53 with the Chiefs. Levy had been a HC in the CFL for 5 years prior, as well as a college HC for over a decade.
Buddy Ryan got his shot as a HC at 55. Had been an assistant in the NFL for 18 seasons. Still, he was the DC of the Super Bowl champs and quite possibly the greatest single season defense in NFL history.
Romeo Crennel was named the Cleveland Browns HC at the age of 58. Crennel had never been a HC at any level prior, with 24 seasons as a NFL assistant, 6 as coordinator.
Bruce Arians was named interim HC of the Colts at the age of 60. Arians was hired as HC of the Cardinals the next year, at 61. Arians had spent 19 years as an NFL assistant (9 as a coordinator), though he did have 6 seasons of college HC experience at Temple.
David Culley became HC of the Houston Texans at 65. 27 years as an NFL assistant. Never a coordinator in any of those 27 seasons. 16 years as a college coach, all as an assistant.
No previous NFL HC is totally comparable to David Culley. No one had ever hired a 65 yeal old with zero HC experience and zero seasons as a coordinator until the Texans did. This is unique. I've tried to find the closest comparisons. But they're not the same.