Someone please explain how there can be an alternative to capitalism

Un/fortunately, capitalism seems to be a product of human psychology (we tend to want more things, for whatever reason) so trying to move away from it in any meaningful sense if probably a doomed excersce in anything but a very altruistic society (we're not, really) or a post-scarcity society (not even close).

I might be wrong here, but that's just my own view on the matter.

Commerce is a function of human psychology, Capitalism is simply a method for distributing investment capital.