What are the causes of the Spartan population crisis starting in the fifth century BC?

Question

The population of the citizen caste of the ancient Greek city-state of Sparta fell dramatically starting in the fifth century BC. It never recovered until reformer kings of the third century BC began to enfranchise non-Spartiates. Why did this shortfall occur?

Answer 1

In addition; the Spartan population crisis was a product of multiple interrelated factors: demographic challenges, economic inequality, rigid social structures, and continuous warfare. While the Spartan system created one of the most formidable military states in history, its inflexibility and exclusivity ultimately led to its decline. The lessons of Spartan history underscore the dangers of failing to adapt to changing circumstances and the consequences of an overly rigid societal framework.

Answer 2

A terrible earthquake localized in the city of Sparta in the 460s BC caused massive destruction of houses and public buildings. This killed a great number of Spartiates. Normal populations tend to recover, but the Spartiates did not. This cannot have only been due to war losses in the fifth century BC. Part of the problem was that wealth had concentrated into few hands, despite the Spartiate belief in equality. Another problem was the Spartiate refusal to enfranchise non-Spartiates. Another was the high-capital system of education, by which Spartiate youths were given an education so expensive that only one or two sons per family were produced; often one or both died in war. A demographic factor involved was also the high status of Spartiate women, which correlates with low rates of reproduction in many demographic regimes.