You never stop needing orcs. And in your next chapter you will have another new good, Mana, that you will always need to have. And then in the next chapter Divine Seeds are added and you will need those forever too. And then each of the next three chapters introduces Sentient goods that are made in your normal factories. And then the next two chapters give you a break from new goods. And then chapters 17+ start adding more new goods. The first seven chapters are so simple compared to chapters 8+.