College football coaches have a track record of failing in the NFL, with Urban Meyer being the most recent predictable casualty. The interesting question is “why”? The most stated answer is simple: Because the player-coach power dynamics are completely different.
In college, the coach is the centerpiece of the team, his players are short-term by the very nature of college, and he’s the one who gets the megadeal. In the pros, the players are the centerpiece of the team, most coaches are expendable and expected to be tossed aside at the slightest failure, and the players know it. Free agency and bigger player contracts have not exactly swung things in favor of the coaches, but as the tale of Lou Holtz and the Jets shows, the same dynamic existed long before 1993.
The other issue is that the gap between the best and worst pro players is a lot smaller than the gap between the best and worst Division 1 college players. There’s no “coasting through a week against the paid tomato can”, as the point spreads show. The biggest NFL point spread of all time was only 28 points for the Broncos against the Jaguars in 2013, and it was not covered by the favorite. Meanwhile seemingly every Week 1 (and many subsequent ones) power program game is so lopsided that most sportsbooks don’t even bother with moneyline (straight win-loss) options at all.