It is said that single ideology is the appanage of dictatorship and totalitarian regimes. When was it born? Was it born with Communism ? With Nazism ? Or was it born, way before ? With Christianity for example.
Single ideology is the shrinking of many trends of beliefs into one. It's a bit what Christianity had done. It first reduced different faiths into one. Then it tried to merge many different ways of perceiving the world into one, as well as many tolerances into one.
It was soon caught up with, by another single ideology : Islam. Together, they almost shared the world. But they both are issued from a much older single ideology : Judaism, where all the gods were merged into a single one.
Today, single ideology is all directed into Consumerism.