The ideas of personal property and wage labor are certainly not emergent properties of the universe. We could just as easily have chosen collective ownership with equal distribution of the fruits of socially compelled labor, trial by combat to see who gets the most stuff, serfs being fed by their masters who effectively own them, everyone feeding himself directly from the land which is owned by no one, everyone feeding himself directly from the land which was cleared of competitors by deliberate genocide, etc. All have been practiced at one point or another.
An economy based on property ownership, investment, and labor is absolutely a system created by humanity, though you could argue many of its observed properties are emergent.
The key in my comment is the difference between "built" (as in: purposefully designed and built, like it happens with software) and "created" (as in: you can accidentally create something). But I know that human language isn't so well defined and other people can give different meanings to those terms... because nobody "built" English!
Regarding "We could just as easily have chosen" I don't agree at all on "easily". Contrary to many theories which say or imply that, people's minds aren't blank slates that can be easily programmed (not to mention re-programmed) to adapt to any social engineering project. Countless examples in history prove this.
An economy based on property ownership, investment, and labor is absolutely a system created by humanity, though you could argue many of its observed properties are emergent.