I remember reading a study recently about the health aspects of power disparity. It concluded hierarchical social structures impose significant physical and mental health risks on those at the bottom. Unfortunately I can't find the source.
The posture that show higher status, straight back, looking to the front and not down, relaxed muscles, etc.. need less energy and is better for your health.
Another interesting though is how good food makes you bigger an taller.
So, however is low in the hierarchy, is always less strong and in worst shape, what makes them to get less food, and so on.. It's easy to see how a feedback of this kind begins.
Of course, all this is carry on to the next generation by several dynamics.
I try to remember all this when I hear how some communities are hopeless or just 'don't want to work'.