Like the quarterback that sets a franchise up for 5+ years of success or turmoil for 5 years.
A new head coach, all new assistants, training staff, in game adjustments, clock management, could set this team up or destroy it.
When Billick was fired, the same "fear", consternation, gripped players, fans alike. While Harbs had his issues, a bottomless pit of a dog house, in game management, he also brought us what 6, 7 division titles, and couple of conference championship games, several ending in heartbreaking fashion, two missed field goals, a dropped/fumbled touchdown/two point conversion. A miraculous last second 70+ yard bomb to win and go to a Super Bowl, which they won, despite a huge power "failure" just after half time.
Yes, Harbs had his issues, most if not all coaches do, but hopefully the next head coach is at least as winning as Harbs.