Humans were constrained by their material conditions. Now that those material conditions have changed, their behaviors have changed to match. This is not a fixed state of affairs. Humans continue to transition between stages just like every other living being.

Greed is as much a part of modern human nature as fear and love. And it is the product of a social condition that rewards growth, punishes disobedience, and requires a larger community to reproduce itself. It is a consequence of social conditioning executed iteratively from parent to child. And a consequence of statistical survival and prosperity played out over populations.

What defines human action is not the basic libidinal impulse, but the interplay between people and their environments over lifetimes and generations. That's not socialism or capitalism at its root. Socialism and capitalism are simply fruits grown from the post-industrial branches of the tree of human history.