I’m not quite sure of your point—the cart was obviously found in a swamp and would have been poorly suited to hauling things up “steep hills”. I would at least have used a spoked wheel if I were arguing the obvious need of a handcart, the weight and stability difference over rough terrain is quite large. That, or provided video evidence you want to haul a solid wood cart up a steep hill with groceries.

I’m pointing out projecting modern needs backwards out of speculation isn’t likely to yield much understanding of why someone didn’t invent a handcart in precolumbian mesoamerica. Jared Diamond at least compares the material conditions of the two sets of continents—that seems like a decent tactic for approaching the past, even if I do have large complaints with his confident narratives.