In fact, when there are fewer wars in the Three Kingdoms, that place will be richer. For example, the four states of Qing Ji, which were surrounded by Yuan Shao, were not invaded by the war, but were all very rich. You can see that in the battle of Guandu, Yuan Shao's war grain has never been broken, and it is endless.
Another example is Liu Zhang and his son in Yizhou, West Shu, where people live and work in peace and contentment, and there is a steady stream of food and grass. Later, Zhuge Liang went to the Northern Expedition. Although the food supply for soldiers was sometimes difficult, it was not difficult to see the wealth of Yizhou by a corner of the land.
Because there is no exact data about the States in the Three Kingdoms period, we can share it, so it is really hard to say that the richest areas are inconclusive.