The Seattle coach and Bill OBrien (for a while were exception), but Carroll had been a head coach in New England. Bill Walsh was a head coach of a CFL team before bouncing between college and NFL assistant coaching jobs, before leaving as Stanfords coach to take the San Fran HC job.
One difference between college and the PROs is that in college, the HC is god, he or she control pretty much every aspect of players lives, the HC can make a kids life miserable and the kid has little or no recourse. In the PROs, the HC has to motivate men that are making considerable fortunes, he or she can threaten to cut a high draft choice, but that only means that player gets a shot with another team. Bill Walsh got that he had to motivate men making fortunes to want to win, high strung college coaches like Steve Spurrier and Nick Saban did not. I see Meyer becoming the latter type of NFL coach, he will spend 2-3 years being flummoxed about why the schemes that worked so well in college dont work in the NFL, and he will have too big an ego to look inward and see that his methods of dealing with high paid men is the root cause.