Another cause of Sparta's downfall was its failure to modify the rigid Lycurgan system to accommodate a pan-Hellenic system accompanied by wealth. Sparta simply believed that the Lycurgan system did not need to be altered. Furthermore, they were against Spartans having too much wealth or personal power. As a result, the Lycurgan system's rigidity produced a closed society plagued by the effects of inbreeding. Some historians agree that "the Spartan hegemony 'perished through 'oliganthropia'' - a lack of men. This is not because of a population decrease in Laconia but just a lack of men of the Spartan citizen class who could serve as hoplites, called 'homoioi' or 'Spartiates.'" The number of men that Sparta could call upon to send into battle diminished appreciably during the 5th and early 4th centuries B.C. This was not solely due to reduced numbers of men but also partly because they were loathe to leave Laconia unguarded and tended to send fewer men to battle than they could have. In the 5th century battle at Thermopylae against the Persians, only 300 Spartans and 1,000 allies held off the massive invasion of Persia's King Xerxes that is estimated to number over 120,000 men. According to Herodotus, however, there were probably 8,000 Spartiates available to be deployed (Scipio, 2005).

             Sparta tended to rely on its training and conditioning to the exclusion of developing its tactical prowess. They were relatively "tactically naive" and could be outwitted on the field of battle. This is, in fact, what happened when they were outmaneuvered by the Athenians in 426 B.C. at Olpae and again at the Battle of Haliartos in 395 B.C. The Spartans were at a disadvantage whenever they could not "out-muscle" or scare off their opponents with their reputation, particularly when their opponents had a competent leader (Scipio, 2005). .

             Another factor in Sparta's decline was the rise of mercenary armies-troops hired and paid to fight-in use by the Greeks.