Anthropology classes teach that the parent comment is true: hunter-gatherer societies are much more energy efficient. Every step of modernization, from animal to machine power, decreases energy efficiency but increases intensity: food can be made more quickly and in less space. Consider that animals are more powerful, but require food and water of their own. Tractors are more powerful still, but require fuel, steel, and huge industries that bring those two together.
The best citation I have off hand is this https://anthropology.artsci.wustl.edu/courses/wucrsl/L48/361...