Lack of infrastructure and resources: Alexander's empire was vast, but it lacked the infrastructure and resources needed to support a centralized administration. This made it difficult to maintain control over distant territories.
Cultural resistance: The peoples of the conquered territories were often resistant to Greek rule, which led to rebellions and uprisings. This made it difficult for the Greeks to maintain control.
Military overextension: Alexander's empire was simply too large to be effectively defended. The Greek armies were stretched thin, and they were often unable to respond to threats from both within and outside the empire.
Economic decline: The conquests of Alexander the Great had a negative impact on the economy of Greece. The constant warfare disrupted trade and commerce, and the influx of gold and silver from the conquests led to inflation.
Changing political landscape: The rise of Rome and other powerful states in the Mediterranean region challenged the dominance of the Greek city-states. This made it difficult for the Greeks to maintain control of their empire.