Why did the Greeks not develop the inner regions of the mainland, but the main colonies on the coast?

– To get to the inner regions of the mainland, military force was required, since there could be strong opponents.
– Colonization had primarily economic knowledge. It was possible to trade profitably through the colonies. In Greece, there was something in abundance (potters’ production), but something was not enough, for example, bread due to a lack of arable land and fertile plains, so it was profitable to trade, not conquer. They achieved their goal. Their colonies in the Black Sea region – Olbia, Kepy and others – can serve as a model.