There's a major college football program that requires it's head coach to win nine games a season in order to keep his job. The nine wins a season came about because those were the number of wins a former highly successful coach established over many years and the fact that a former coach was fired by the school's athletic director despite reaching the nine-win total.
The idea is that the program should never fall below that mark because it's better than nearly all the programs it plays on a yearly basis. To fall below that mark would be a sign of mediocrity.
The nine-wins-a-season requirement allows no mercy if a team were to experience a high number of injuries. It doesn't care if a single recruiting class bombed out thus limiting depth and/or experience. It does not care if you are starting a new quarterback in any given season and the reduction of offense that comes with new starters at that position.
Because it allows for no extenuating circumstance, the "Nine Wins A Season" standard is too harsh. It does not allow for the very real prospect of a "down year".
It may also be detrimental to the program. Coaches in position to lose their jobs based only on wins and losses may cut corners. They may yank redshirts without regard to the affects on the player's entire career.
As a result, said program will find itself in a lather, rinse, repeat cycle of hiring and firing coaches, a deal with the real cost of doing so. Not only must buyouts be paid, but the cycle of bringing together staff, players and fans must be begin anew. Any coach will have a learning curve around his new environment as will his staff.
Obviously this is Nebraska we're talking about, but I wonder were you to apply that same standard to any other program in the nation, would it not look silly?