Why did Greece s city states develop so differently from each other?
Look at a topographical map of Greece and compare it to a map of the major city states. Notice how most were surrounded by mountains, the sea or both. This kind of topography tends to limit casual interchange between population centers. In other words, the majority of the people are born, live and die within a small geographic and cultural sphere.
Because they were different from each other. Five miles was a long way away back then.