You can thank Nixon and the abandoning of the Gold Standard in 1971 for this problem.

It allowed government to print $ unchecked. When new $ gets printed, it goes to the corporations/rich first, causing inflation for everyone else. This artificially creates an extremely wealthy class.

Not saying the Gold Standard is the solution - it had its own set of problems. But the untying of money from a real, hard asset is what makes the existence of the ultra-rich possible.