Nah, Corinth was considered important too, but Sparta is much better known in the modern world. And Plato is pretty important here. Sparta gets relatively high

Nah, Corinth was considered important too, but Sparta is much better known in the modern world. And Plato is pretty important here. Sparta gets relatively high praise in the Republic which is probably one of the more influential books from its era. Platonism's enormous influence on Christianity ensured that this praise would remain relevant even into the modern era.