[omginternets]

It's also possible (and, I would argue, more probable) that they fail because for any sedentary peoples, the accumulation of material wealth is inevitable, and such accumulation is unequal. Thus, some degree of "capitalist individualism" grows organically out of sedentary societies.

The only successful societies with anything resembling fully-shared ownership are those which can't accumulate much of anything.

I say this not to defend ultra-liberal capitalism or anything, but rather to point out that utopias tend to be very artificial (and therefore short-lived) constructs.

[Symmetry]

It's also wrapped up in the move from hunting and gathering to farming. Hunting is relatively random and while skill plays a role you can't rely on it. Also excess meat won't last too long so why not share? Farming is more reliable and when bad luck hits it often hits an entire group at once. And it involved more unpleasant labor to farm a lot of food meaning incentives become more important.

[zepto]

Ultra-liberal capitalism is also very artificial

[omginternets]

Respectfully, that's a very loaded statement, as evidenced by the absence of a clearly-stated point. My reaction is twofold:

1. You seem to be implying that ultra-liberal capitalist societies abound. I disagree to the extent that most economies/political-systems incorporate social elements that tend to push the dial back towards resource sharing. I do, however, concede that there has been a trend towards liberalism in recent decades, but this is accompanied by increasing social instability. I don't see how your comment constitutes a counter-point in this respect.

2. It's not really artificial given the two priors discussed above:

    a) accumulation of wealth (and the subsequent inequalities in entrains)

    b) low social trust

Again, this should not be interpreted as a defense of ultra-liberal capitalism, but I think it's so entrenched precisely because it follows naturally from the aforementioned preconditions.