In his work “The Collapse of Complex Societies,” Joseph Tainter argued that societies are prone to collapse when the marginal returns on additional complexity begin to plateau and then decrease.
A society might find itself so complex—with so many specialists, interconnections, and layers of hierarchy to maintain—that it has few or no resources left to respond to a new problem by adding more complexity, or even by maintaining its present level of complexity. In these circumstances, a society might economize by shedding layers of complexity: losing specializations, separating previously connected components, or—my favorite—shedding layers of hierarchy.