It is not just a number, as it is for people who just save a few dollars, for whom it really is just a number until they withdraw money to use it. The billionaire's money is not "money", it is actual working assets, and the abstraction of turning this into a number does a terrible job, the result now misunderstood by many. Assets being companies doing stuff mostly (holding non-control-giving paper assets is different and not what being a top capitalist is about, only used as an additional tool below the actual goal). Which they fully control (the small investor does not even have any control worth mentioning when they own shares of a public company).

They don't just play with money, they play with real things! And they want to play with ever bigger real things. They don't just want to improve some minor product. They want to control the fate of civilization.

OT:

I hate this money view with a passion, this is what too many people discussing wealth inequality issues get wrong. This is not Scrooge McDuck and his money pile. Money is an abstraction, and it is misused terribly, hiding what is actually going on for too many observers who then go on to discuss "numbers".

That is also why the idea to "just redistribute the money of the rich" is a failure. It isn't money! It is actual real complex organizations. And you can't just make everything into a public company, and also, even when they are, for better or worse owners don't lead like managers. Doing the socialism thing (I grew up in the GDR) where everybody owns a tiny bit of everything just does not work the same.

We will have to look at what those super-rich are actually doing, case by individual case of ownership, not just look at some abstract numbers. Sometimes concentrated control over a lot of assets is a good thing, and other times it is not. Ignoring the objection of "who would control that?", because right now they control themselves so it's never nobody.