After the Jinns realized that the Wanderers had the option to leave the continent, they all started to change their minds.
If they were left behind to fight against the Azothralls, what awaited them was a slow, painful annihilation.
Of course, there were other options—for example, the Jinns could form a megapolis and live together as one.
But this was not a good option for them. Jinns were prideful to begin with.
Perhaps in the first few months, or even years, of living together, they might be able to accept it. But as time went on, that choice would start to bother them. They'd begin to see it not as a strategic decision, but as an act of cowardice. And the shame would follow.
And even if they did choose that path, the Azothralls could still strike using guerrilla tactics, weakening their forces while strengthening the enemy's.