To show you an extreme example, even literal dictators can't do whatever they please. Those in positions of power must either appease those who put them in that position, or be ousted for someone who will. They are bound by the system as much as anyone else. That's not to say that they can't have any influence of course, but the point is it's not that easy.
Watch season 3 and 4 of The Wire if you're interested in watching an idealistic, "I'm gonna not be as bad as my predecessors" man become the mayor and then become a complete slave to the system. It's inevitable.
You can also read this, it might help you realise that things are the way they are for reasons beyond malice sometimes, and we need to understand that if we want to have a chance at reforming anything: https://www.slatestarcodexabridged.com/Meditations-On-Moloch
I used to work in the building on the right. Thanks for triggering some nostalgia!