So conflicts like this can never actually end? Any peace is an illusion, just a pause before the next turn of the wheel? I don't have such a pessimistic view.

There have been conflicts like this throughout history that really have permanently faded off back into the past, with the modern descendants living perfectly fine together and no longer concerned about those original causes of the conflict. If they end up with some new reason to fight in the future they may fight again, of course, and they may even dredge up those old conflicts as part of their propaganda. But it would be a new conflict, not the old one reborn. They're not going to just up and start fighting again for no new reason.