People are entitled to as much of "the pie" as they earn, win, or someone gives or wills to them. "The pie" is not finite.
A church story for you:
The Catholic Church in Mexico once owned a huge portion of the land and their revenues they produced. You might compare that to the rich owning a dis-appropriate amount of the USA's wealth. It got to be that the Church was challenging the government because of their wealth and influence. Yeah, just like the rich manipulating media and congressmen.
The Catholic Church doesn't own a single acre of land now. It got so ridiculous that the government took it all away from them, a vote and the slash of the pen. They kept the magnificent churches but don't own the land they are sitting on. You can compare that to motivated bunch of citizens who finally vote to end the inequality.
Still left were the rich who owned most of the rest of the land. Huge chunks of that were taken away from them and given to the poor not so very long ago. Some votes and the slash of the pen again.
A vote and a slash of the pen is all it takes to correct this in the USA as well.