I feel like this is a very cynical way of looking at things.
I know some excellent people in leadership that have been promoted from lower level management jobs. I’m not sure the career change made them no longer care about people.
That doesn’t mean they don’t care though. Now this could come from spending time at a company where the executives were only ~3 levels of indirection from devs.
It's not that the career change makes them not care about people. It's that it's practically impossible to get into upper management without eating others. People who don't embrace their sociopathic tendencies don't make it - they get out-competed by those who do. The very occasional exception just proves the rule, and usually doesn't last in any case because once they get to that point, they still have to compete to remain there.
I know some excellent people in leadership that have been promoted from lower level management jobs. I’m not sure the career change made them no longer care about people.