Broadly speaking, there are two reasons managers fail: either A) they don't do a good job representing the work of their team sideways or upwards or B) they don't do a good job representing and cascading the strategic direction from leadership.
While there are many specific modes of failure, they all essentially boil down to one (or both!) of those gaps. The article talks about the Peter Principle where ICs are promoted without management skills, but the flip side of managers who only studied management with no practical expertise is a greater peril. It's obvious when the former is failing, whereas the latter can spin a web of bullshit long enough to continuously fail upwards.