I think one thing is that in a lot of companies there still is the belief that your pay is determined by the number of people you have under you and that a manager always has to make more than than the people they manage.
Surely it’s insane economics for the company though. My management skills must be almost useless (and I’m considered an ok manager) compared to my dev skills. I can’t understand what’s in it for the company to make EVERYONE into crap managers AND pay them more AND make them unhappy AND ensure that only inexperienced juniors have time to actually do work. Just don’t get it. But every company wants to do it.