Very True
"I still wonder just how many managers follow these sorts of things at all."
Around 5% Those are the ones that rise in bad times, and end up being CEO some day.
Of the rest, 50% are people who keep doing what they were doing before they were promoted. These are the deadwood of Parkinson's law. They have reached their level of incompetence.
Another 40% or so are the 'yes' men. They may be promoted in good times, but they are a nightmare to work for and a pain for superiors to deal with in bad times.
The remaining 5% or so are the ones who don't get it yet. A lot of them have promise, but it takes several failures before you begin to understand. I was one of those for around 10 years before I 'got it'.