Why did states appear at different times?

For a new state to appear on the political arena, a huge number of factors are needed, which will combine into one. The formation of a state is not a momentary process, it is a huge period of time. There must be at least a cultural layer, due to which people are united into a state, there must be a strong economy so that this state is not crushed by other, more powerful states, and a huge number of all kinds of factors.