Absolutely, lived experiences shape our expectations about how the world- and society-at-large treats people, and how they ought to be (re)organized to maximize benefits.

You point to fundamentally different assumptions, and as a whole I agree with that too. I think that anarchists put less emphasis on human nature per se than they do on ethical organization practices--they preach a scheme of purely voluntary self-organization mostly from an ethical standpoint, and this stance implies that they view human agency as the most important ethical question, rather than meeting basic needs (communism) or castrating exploitative practices in labor (socialism/Marxism). Libertarians seem to be whistling another tune, more along the lines of anarchism but by also tying capitalist success to a person's ability to steer their path in life. Anarchists think that free association will provide for those who need by virtue of a sense of humanistic camaraderie.

I'm not arguing for or against anything here or anything you've said, and I'm not sure I'm doing much at all except a fun exercise to clarify the varying motivations of people in their quest to restructure economies and societies. But it is interesting to consider and feels good to put to words.