I think the first thing people have to accept is being a successful NFL HC is a very tough job and much tougher after FA entered into it. The turnover is 20-25% every year, like clockwork. There are really only two HC's that have weathered the storm well, Belichick and Reid. How well could coaches like Lombardi, who didn't fare as well at WAS, Landry, Noll, Levy and Walsh have done when the first sign of success brings the vultures? Think that Steel Curtain and Doomsday wouldn't have been difficult to hold together. Backup QB's were better back then when today, not all 32 teams can find a suitable QB1. And if you are a HC with a QB problem, you have a Real problem.
Petrino, Saban and Spurrier couldn't get back to college fast enough once they got a taste of legal pay to play. They also got their first taste of the tail wagging the dog with players' salaries.
If you took Belichick out of NE and dropped him into one of the lower 8 teams, as heralded as he is, it would take him at least 2 seasons maybe 3 or 4 depending on cap space, to get back to close to what he's built in NE. Time used to be the HC's ally and now it is the enemy. Garrett lucked out with the Cowboys that he could withstand a really poorly coached 4-12 season but other HC's get canned for better than that. The difference with a Belichick is that it would take him time but the team would improve form where it was immediately.
