In college I took a class in engineering business management. Many of the things I learned in that class made a lot of sense, so I certainly wouldn't deride the teaching of how business works in general.

It seemed to me that every management technique (lean, kanban, kaizen, six sigma, prince2) came with a high profile success story attributed to it. That's reasonable enough. But every time a management technique also had a high profile failure story at a second company, it was never attributed to a failing of the system; it was that the second company hadn't believed in it hard enough. If only they'd completely gone for broke, throwing caution to the wind, it would have worked!

The bias towards only seeing the good in these techniques made it jolly difficult to choose between them when they offered contradictory advice.