Greece and the conflicts between the City-states

Everyone knows about how Greece was weakened by the constant rivalry between the differing city-states, such as Sparta and Athens fighting for 27 years for supremacy, and later conflict between Thebes and Sparta where Epaminondas slaughtered the Spartiate army in the battle of Leuctra, the most important battle of the 4th century after Chaerona and Gaugemela. Yet without this constant conflict, Greece would never have been unique. The city-states would be just some more cities, this time not centered over a river. And it is not like the city states of Greece were unique in their conflict, because the city-states like Nineveh, Babylon, Ashur, and Ur were constantly fighting along the Tigris and Euphrates, and yet the Greek fighting is remembered more. A possible reason for this would be that our society has been accustomed to the relative peace of the 2oth and 21st century, where wars are only occuring relatively often, as opposed to the constant pace they were fought in the ancient world. In any case, the conflict between city-states was the norm, not the exception, and the conflict forced the city-states to streamline how their governments worked, and forced anachronisms like the Ephors in Sparta to be destroyed in the interest of the state.