The relevant "large scale" would be the largest sustainable scale, wouldn't it? If we calculate the peak power output of a hydrogen bomb to be a few yottawatts, that doesn't mean we've created a sustainable nuclear power output of a few yottawatts, does it? It means we've created an explosion that has used up all its fuel.
You make a fair point about the evidence for long-term egalitarianism. The best evidence we've got is that everywhere that Europeans explored they found a mix of societies ranging from slave-owning to radically egalitarian (what you're using the term "equity" for), so it seems reasonable to assume that the same sort of mix has generally always been present. That's why I said "some of them egalitarian", and not "all of them egalitarian", though you're correct to point out that the sort of "demand sharing" egalitarianism that I'm thinking of might be beside the point.
Although... that kind of demand-sharing radical egalitarianism does prevent the accumulation of capital, which leads to:
I think you might be confusing capitalism with free markets. Capitalism is about production decisions being made by those who have accumulated large amounts of financial or physical capital, hence its name. (And it's usually limited to non-government accumulation of capital, and it's usually applied to the deployment of capital specifically for profit-making.) I don't know of any serious scholar who would apply "capitalism" to barter systems. Even Fernand Braudel's excellent Civilization and Capitalism has been criticized by other scholars for placing the start of capitalism too far back into the medieval period, when many of the tools for deploying large amounts of non-government financial capital were being developed. (Although there are other scholars who have argued that its starting point should be pushed even further back into earlier Islamic or Persian civilizations. But nobody has said "let's find any old barter system and call it capitalism!")
As Braudel and others have pointed out, capitalism has often has had an uncomfortable oppositional relationship with free markets, since what's a quicker way to make a return on your capital investment than to use it to distort markets? That's why we need anti-monopoly and anti-collusion laws, and why they're so frequently undermined by capitalists. It's why elements of free markets like price transparency have been opposed by basically every capitalist you'll ever meet. (That's been the case at every company I've worked at, anyway - nothing is kept more confidential than the terms of large deals. This is a classic pro-capitalist, anti-free-market move, and it's one sign that we have more of a capitalist system than a free-market system.)
When you say "equal rights", do you mean equal rights to eat the same food as anybody else, or to live in the same house as anybody else, no matter how much money you have? Those are the kinds of equal rights that have been found in many (but not all, don't get me wrong!) societies. Or are you limiting equal rights to its capitalist sacredness-of-private-property definition?
(I won't get into the debate about whether barter systems as a permanent feature of an economic system have ever been anything more than a Just So story.
But that's a thing, too.)
