There is every reason to believe that the wars between the city states, when they do not result in the destruction of a city like Yaramuke, are largely theatrical - at least in Athas during the time of the campaign setting.
We are assured that there are wars, but nothing much comes of it. This reminds me of the situation in the novel 1984, the state of war which is described in “The Theory and Practice of Oligarchical Collectivism” - a fictional book in a fictional novel.
https://www.bibliotecapleyades.net/sociopolitica/sociopol_bigbrother13.htm
This is known only to the Sorcerer Kings themselves. All the city states are held in a constant state of readiness, justifying the harsh conditions imposed on the populace.