He started his career as a coach at 23 years old and for the first decade of his career, Weis was a HS assistant, GA/Volunteer and HS Head Coach. He put his time in learning the game from the most basic level for a decade before getting in with an NFL team, where he had to put in countless hours and 7 more years to become competent at the NFL level before he finally became an OC in 1997, 18 years after beginning his football career. At that point, he was absolutely a "football guy".
I'm not saying that it can't happen, but Weis is probably the best example and it took him almost 20 years of coaching to reach the Coordinator level in the NFL. I feel like I remember you saying that you played back in the day, so I'm surprised you have this opinion that I think is so far out there. The amount of game knowledge you have to have to coordinate a high school offense well, is so far beyond the average football fan's grasp of the game it's not even funny, let alone the advanced concepts in the collegiate and pro games.