If you think about it, conflict has a “lock in” effect. Once it starts, it locks the participants into a new logic or storyline. And as the conflict continues, that lock in effect gets more and more pronounced. So it was, for example, the First Great War. Few anticipated how horrible the fighting would be. But it was truly awful. And that awfulness made it more difficult to end it. One had to justify the huge sacrifice.
Sadly, this is why there are times when the only way to get beyond a conflict is to wait for the leaders who started it to exit the stage. Napoleon had to be exiled or killed. There was no other choice to getting beyond the dreadful Napoleonic wars. Thus you get conflict resolution by creating a disconnect. In other words, you sacrifice continuity.
On a more personal level, we talk of “starting over” or “making a fresh start”. The need to do that is in fact, a cost of failing to manage conflict. And managing conflict starts with understanding the lock in effects.