[dragonwriter]

> which means yeah, you have done the entry work somewhere

Even if so, that somewhere doesn't have to be the same industry you go with your first (usually not top-level) leadership position, and neither of those may be the industry in which you end up moving into a top-level leadership position.

[mercer]

The vast majority of managers I've had, whether product or program managers, had very little understanding or experience with the job of programming.

In fact, i suspect more than half of them basically failed upwards. I can't be sure about this, because in many cases I could only see the piss-poor job they were currently doing, but I've experienced the incompetent junior-to-senior manager pipeline up close often enough that I wouldn't be surprised these senior managers were previously incompetent junior managers.