I think you're giving large scale socialism a far more organic origin than there was. The idea of communal economies is very old, especially in smaller scales. Trying to scale that and apply it in a democratic society still requires someone at some point saying, hey, let's try this, and then having to justify that policy to build support for it.
European socialism didn't happen unilaterally. It didn't just happen by natural societal evolution, as you seem to imply, either. Socialism isn't the next logical and natural evolutionary step in the development of societies as much as you would like that to be the case. It grew in popularity in part because it is quite efficient at giving fewer people power over large societies. Capitalism, by itself doesn't most naturally do that. Crony capitalism, which is a function of socialism, does naturally do that.
Capitalism is a far more naturally evolved economic system because it is the default economy for human nature. No matter what socialism tries to provide, or ban, or control, it must place arbitrary limitations that are less natural to the needs and wants of the people. Economies will still exist for what the people really need and want.
It's true that tribal cultures are more communal in their economies, but a tribe isn't a scale much beyond a family unit. The inner economy in my family is not capitalist. It is communal as most families are. My son doesn't have to trade something of value in return for food. Tribal economies are like that. Communal economies work fine in families and scales of community where homogeneity of purpose can exist. But where there is wide diversity, it's much harder to pull off without creating losers for every winner. We're all still traders by nature and have been since recorded history. That's still the most natural economy.
I won't continue the dorm room discussion. I'll just say there are many things in your observations that I believe to be in error. Hierarchies appear to be the common thread among large organized groups across all cultures. Economic systems vary. What the future holds when the population increases by 50%, I don't think you've managed to convince me that free market democracy is the default state of affairs.