I heard a better explanation than that when I was in Mayan land. The guide, Ph. D. candidate, told us they had class warfare, just like the US is doing. The elites kept everything to themselves, the peons knew nothing about math or astronomy, reading or writing. One day they up and killed all of the elites and no body knew how to do the cool stuff any longer. That sounded right to me. That is what most people would do, or at least want to do. We have not been oppressed enough for long enough. Only people emigrating from communist countries know what that is like. Ask one.