I still want to know what the Steelers do in their interview process to find these guys. Tomlin lasted 19 seasons, his predecessor, Bill Cowher was there for 15, and could have lasted another dozen or so if he wanted to continue coaching (his wife's health okay a major role in his early retirement).
The amazing thing is those two combined only coached the Steelers one season more than Chuck Noll, Cowher's predecessor did on his own. To put things into perspective, opening day 1969 was Noll's first game as Steelers head coach. The team has had three head coaches since the 1968 season ended, which ended with a Jets Super Bowl win.
Training camp for Noll's first season started before Woodstock, basically at the time of the first moon landing and before the Beatles finished recording Abbey Road, their last album (last one recorded, Let It Be was their last original album released). In that time they've had three head coaches. Some teams have done that in a year.