They're too big to fail.
As I was reading through Dr. Willingham's When Can You Trust the Experts last night it hit me: many of these bad ideas (e.g., Marzano, learning styles, no zero policies) are now "too big to fail." Too many people have made their careers on these ideas. Too many people have careers based on these ideas (see below). So even if you could get through the "it must be right because everyone believes it" mentality, you would still have an uphill fight--displacing people in administration that base their livelihoods on (essentially) wasting time and money. (And of course, these people would have an added incentive to NOT believe what they were doing was useless, and they're in power...which means getting through that "this doesn't work/this isn't real" barrier may very well be impossible.)
My district alone has a seven-person "Accountability and Assessment" department that includes:
Director of Assessment and Accountability
Program Manager for Testing, Grants, Development & Evaluation
Program Manager for Assessment and Data Analysis
Program Evaluator and Data Analyst
Test Development Specialist
Test Warehouse Operator
We won't ask why a seven-person department needs a Director and two managers. Gotta love that near 1:1 ratio of managers to non-managers! (And I got $5 that says that the clerical assistant does more real [honest] work than the managers and director combined--and for half their salary. ;) )
Potential solution: Education grad schools need to focus more on how to conduct and/or review research. This will (hopefully...) start putting more knowledgeable people in power down the road, thus avoiding falling for these bad ideas.
Just heard this and thought it apropos: "It is difficult to get a man to understand something, when his salary depends upon his not understanding it!"--Upton Sinclair