http://www.idbsu.edu/courses/hy101/peloponn/17.htm

Results of the War

 Sparta won the war, but scarcely knew what to do with the fruits of victory. Her attempts to lead the Greeks were heavy-handed and soon called forth new champions of liberty. Chief among these was Thebes. But Sparta did not become a great city, nor did it build a new empire.

 Did the war harm the Greeks as a whole? That's one I will not answer here, but rather will suggest two contrary interpretations. By the first, the war was detrimental because only Athens could have united the Greeks and only a united Greece could have withstood, first Alexander and, later, Rome. Athens' defeat was Greece's defeat.

 By the second argument, Sparta's victory was Greece's victory. A united Greece was never a possibility. More to the point, it was contrary to what the Greeks themselves wanted. Theirs was the world of independent city-states, and Athens was a threat to that world. Sparta's victory preserved Greek liberty--as the Greeks themselves understood the word--for another 250 years.

History of Western Civilization