yes it does, because billionaires exist

Non sequitur.

all economic systems on the planet are controlled by governments,

Not controlled, but highly interfered with. This is a key distinction.

The reason why or how these billionaires got their capital is irrelevant

False. If they acquired wealth by free market processes, they provided wealth in exchange. If they acquired wealth through political plunder, it is a violation of everyone else in the economy.

Once you reach this level of capital accumulation it is pointless to keep accumulating more, it is just hoarding capital.

Again, you keep asserting that there is "hoarding." You are using loaded language as if it constitutes an argument.

1. What is "this level," and how do you determine it?
2. Why do you disregard the economic benefit of investment?
3. Who are you to dictate what is "pointless"?

That is why we government taxation, it serves 2 purposes, to prevent this type of wealth inequality (hoarding) and to prevent high inflation, but it only works when you have competent politicians who are not corrupted and understand how the economic system works.

Political power concentration creates inequality, concentrates wealth in the hands of the politically connected, and has creates the financial system chaos and distortion we are discussing now. It doesn't prevent hoarding, it promotes plunder. It created the very inflation you say we need it to fix. The psychological and economic incentives of such power guarantee corruption. That is a feature, not a bug.