When you mentioned the emergence of art earlier than the writing system, I started thinking that it is because language is a system unlike art. Thinking exclusively through art movements, actually, means to simplify things. It is the moment when an art historian finds abstract work earlier than it has been defined like a movement, and he doesn't know what to do with it.

It is far away from being solely a revolution of art movements. For instance, Caravaggio himself was a revolution in the late 16th century. It doesn't have to be a movement. It might be one person who starts to untangle a novelty.