Julia Steiny recently heard a speaker whose conclusions point to the same problem in education, but from a different aspect:

University of Chicago Prof. Charles Payne spoke recently on the subject of his book So Much Reform, So Little Change. …
“Because you have institutions in which the adults fail to cooperate. Grown-up people unable to work together bedevils the system from bottom to top.”
Yes! Payne is so on to something.
He says, “All decisions are politicized. Failure is valorized. Sit in a teachers lounge and listen to them compete with one another about how much their kids are failing.” When districts actually get good leadership, they chew him up, they buy her out. Payne cites Rudy Crew’s excellent record in Miami and his ignominious departure as only the most recent example.

That’s a proximate cause, but Steiny extrapolates the factor that creates the detrimental setting:

… the central relationship at the heart of public-school districts, big and small, is the structurally adversarial relationship between labor and management. Historically, labor-management stances often erupt into war-like conditions with strikes and the ugly work-to-the-rule labor actions hurtful to children. When school or district grown-ups battle among themselves about who’s entitled to limited, tax-generated resources, students don’t matter.

Unions create a power group whose interests are ultimately distinct from those of school children. They create an environment in which a teacher seeking to advance has incentive to invest in the union structure, rather than proving her or his own value in the objective of the school (i.e., education).