> A single person can entirely overtake democracy when he has billions. He can own press, politicians, etc.

Only if the country is corrupt, a well functioning democracy can't be bought.

This is exactly how a democracy gets corrupted

What happened with Michael Bloomberg?

Worth billions, wanted to run for President, spent hundreds of millions on ads and got nowhere.

That's because he tried to play fair. Look at Sheldon Adelson, I won't talk about US politics, but during the last twenty years he pretty much changed the entire press landscape of Israel subordinating it to Netanyahu. He made a huge impact on Israel politics and public opinion.

well, a hundred other people of similar circumstances not liking him?!

But I keep hearing billionaires wield the power to do whatever they want.

Bloomberg couldn’t even get his parties nomination.

I guess billions doesn’t get you that much power.

False dichotomy. Just because Bloomberg couldn't win the nomination does not mean that billionaires do not hold unjustified political power.