money represents power and whoever has power will have the money.

i think you're looking at this from a very "everyday" perspective - you think of money as something that is passed around and goes from A to B. the system at large does not work that way. just like the earth is flat if you look at any small patch of it but is round when you look at it globally, the economy works very differently whether you look at it at an everyday scale or at a global scale.

on a global scale, things are determined by geopolitical considerations, not by whatever companies or buyers/sellers do. like, that china exports so-and-so many tons of steel and imports so-and-so many tons of pork meat has very little to do with companies working hard to produce these products. it's mostly some globalist philosophy to determine what happens on a global scale. for example, tariffs might completely change the game, if only there is the political will for that. as do free-trade agreements.

again, the same is true for any big country. "money" on a country-level is a fiction. it was invented by banks for complex reasons (mostly to simplify trade) and can be modified as long as it's meaningful to the state's politics. like, the state can just print more money through the federal reserve bank. in fact, it does that all the time. that cannot be explained by simple "trade transactions" as you're imagining them rn. there's abstract and complex and completely non-trivial maths involved in this game. "what happens when the billionaires own everything" only makes sense as a question when you consider that the concept of "owning" stuff is fundamental - which it is not. "Ownership" is a legal construct because the state deems it useful. with a different philosophy, the very concept of "ownership" might lose traction and become meaningless. The question therefore is: What is the political will at a state level?