If you've ever worked in tech management, your experience likely was "IDK, you're senior, you vaguely have an idea what we should do, here, go manage a few folks".
No training, or minimal training. Often with an expectation that of course you can still be a strong technical contributor, because how much time could managing folks possibly take. And then mostly being evaluated based on how your reports delivered.
As long as we follow that approach, we'll struggle with managers doing the right thing, because they neither have learned it, nor have they seen it modelled.
Sure, that expresses in bad manager performance, but often nobody can really see it or tell people what they should do better. Performance review is too late to fix that. (This is, btw, mostly true for employees as well - if you only talk about performance 1-4 times a year, people are being set up to fail)
