Do they end without one side dying off, giving up or leaving? Does the appearance of an external threat end the culture war or make it worse by working with one side? Has there been any time in recorded history when such wars weren't occurring?

We know more about them now, but that doesn't mean they're more or less frequent. Merely better attended.

There's a huge amount of overproduced managers and elites on universities who don't participate in the productive economy, and the culture war is a tool they use to compete among themselves and to create job programs for their class interests. Unless you find an alternative way for those people to compete and transfer wealth to themselves, or you find a way to incorporate them into a productive economy, this is not going to end any time soon.