College OCs tend to have more control over their side than NFL coaches do (often times, NFL coaches call their own plays if theyre an O coach by trade). Recruiting also plays a factor as styles vary for vastly in college than in the Pros. also, no one is saying Mario couldn't hire his own staff. its rare and weird for an HC to hire position coaches before hiring an OC. its what happened last year. you tend to want your OC to have some say in what guys are coming on board. further, OCs recruit whereas NFL you can turn over a roster year over year. in college, youre building a roster from HS kids. you want kids who fit your system.