John Fox came to the AFC West before the 2011 season as the head coach of the Broncos and since then, he and his tree has overgrown the division.
Two seasons ago, the AFC West head coaches were Tom Cable (Raiders), Josh McDaniel (Broncos), Norv Turner (Chargers), and Todd Haley (Chiefs). Then in 2011, three of those coaches were replaced. Cable was replaced by Hue Jackson, Haley was replaced by Romeo Crennel, and the Broncos replaced McDaniel with John Fox And thus the Fox Infiltration began.
Fox took over for McDaniels in Denver and took a reeling Broncos team to the playoffs. The most amazing thing about it was he did it with Tim Tebow at quarterback. Then once in the playoffs, they ousted the Steelers. That success had the rest of the NFL knocking on their door to pick apart their coaching staff to try and find was made it tick.
One of the great improvements the Broncos saw that season was the defense which went from literally the worst in the NFL in both points allowed and yards allowed, to becoming one of the more respected defenses in the league. That improvement was credited to first year defensive coordinator, Dennis Allen.
Reggie McKenzie came to Oakland to become the general manager and his first order of business was to fire Hue Jackson. He, like much of the league, was looking at Denver assistants. But with offensive coordinator Mike McCoy gaining the bulk of the headlines, McKenzie wanted a defensive guy like himself. He interviewed Allen and made him the new coach. All the while McCoy was left without a seat when the music stopped.
The music started up again quickly once the Broncos were knocked out of the playoffs by the Ravens. And McCoy found his seat within the week replacing Norv Turner in San Diego.
Now, the only AFC West team which has a head coach NOT either named John Fox or from his coaching staff is the Chiefs. They scooped up Eagles' former longtime head coach Andy Reid days after he had been fired in Philadelphia.
Fox is familiar with the AFC West. His second job in the NFL was as the defensive backs coach for the Chargers under head coach Bobby Ross. He held that position in San Diego for two seasons (91-92) before he got his first defensive coordinator job for the Raiders in 1994.
Fox was the last defensive coordinator for the Los Angeles Raiders under Art Shell. Then he stayed on as the defensive coordinator for Mike White as the Raiders returned to Oakland in 1995.
If you go by which team Fox had his first coordinator position, one could say the Broncos, Raiders, and Chargers all have coaches from the Art Shell coaching tree.
As far as success of former John Fox coordinators turned head coaches, there is none. Allen and McCoy are the first ones. We have no basis for judging how successful his coaching tree will be as we can with the Bill Belichick tree with has had a great many failures.
That Belichick coaching tree was the flavor of the half decade in the AFC West as well. It's the Fox coaching tree which is replacing the dead ends from the Belichick coaching tree. Josh McDaniel, Romeo Crennel, and Charlie Weis were all buds that didn't bloom once they branched out from the mother tree.
Fox has been a winner in Denver over his two seasons there, taking the Broncos to the playoffs in both his seasons there. His first disciple, Dennis Allen, has begun his head coaching career with a 4-12 in a rough first season in Oakland. Now McCoy is about to embark on his first head job hoping he can get the Chargers to live up to their potential.
This time next season, we should have a pretty good idea if the branches on this tree can live up to its roots. If it can, the AFC West could be the Wild West once again. If not, it will be back to the Raiders with double digit losses, and the Chargers snatching defeat from the jaws of victory. And nobody wants that (at least not the first part).