from Shultziner, D., T. Stevens, M. Stevens, B. A Stewart, R. J Hannagan, and G. Saltini-Semerari. “The causes and scope of political egalitarianism during the Last Glacial: a multi-disciplinary perspective.” Biology and Philosophy 25 (2010): 319-346.
…For the development of hierarchical social structures, for example, social factors are essential but not sufficient—high degrees of resource abundance and stability are also essential. …
By similar logic, scarcity and instability break down hierarchical social structures, e.g. Somalia today, etc. What you get now is a return to small social units adapting to instability & scarcity, but in a situation of crowding and access to modern weaponry, rather than Pleistocene conditions.
Living on Unstable Ground 