That is not how capitalism works.
Once we reach the end of the road for further invention and improvements (even if that is in the form of our own capacity and theoretically there's more), that's when capitalism becomes zero sum. Until than point, capitalism is a way of distributing more resources to people who are better at finding those improvements.
The entire foundational assumption of (Smith's) capitalism is the idea that people who are better at making a profit are exactly who should be given more money to work with, and that this benefits all of society — and while I will agree that the phrase "trickle down economics" doesn't fit reality of the behaviour of billionaires (who act more like aristocrats), that's where that phrase comes from, and it seems to often work up to deca-millionaires at least.
The flaw with this (even in the case of millionaires) is it presumes no parasites. As it happens, both Smith and Marx noticed this, but as history shows, the proponents extolling the virtues of each were not very effective at preventing economic parasites.
If I read an article that titled "this NGO is distributing food and medical aid to the refugees of the conflict" and then on the body of the article I find out that a single guy got all the supplies and the rest got nothing, I would consider the title very misleading.
I'd count that as a sorites problem: https://en.wikipedia.org/wiki/Sorites_paradox
But the distribution for wealth under capitalism isn't "one" person, and capitalism wouldn't work if it was, because nobody else could buy anything with the money, and therefore everyone else would invent a new currency or barter, and then all the money which that one person has would be worthless.
https://www.oxfam.org/en/press-releases/richest-1-bag-nearly...
Also let us not forget other tools that have significantly helped capitalist nations: Slavery, Colonialism, Imperialism, Sanctions, Wars, Coup d'etat's... these have all contributed to what capitalism is today. So yes Capitalism in the grand scheme of things is entirely zero sum.
The data from the Fed show great inequality which can be expected from a zero-sum game. Another example check how under develop DR Congo is in the electronic age, while hardware (and to an extend software) companies are some of the most valuable companies, they all source raw materials from Congo.
Capitalism isn't zero sum because at its core principle are transactions, which are inherently non-zero-sum.
The definition of Communism per the west, is something that always fails by default. The way Chinese define communism is doing whatever it takes to win.
When you remove all the abstract words behind this game, a simple philosophy is if you do the right things you win. You can call it capitalism, communism or whatever you want.