Oh, I understand what you are saying. I never said they experienced it however (well Mide did when she realized what happened during the failed summoning). To them (Mide and Dayan) that's just the way it happened. We, outside the game, can see it as a loop because we know that they are destined to do this again and again.
I don't buy into the Exarch's reasoning for his continued survival (the dark future is set adrift never effect us again, and I just so happened to carve a piece for myself here). I mean, I like him a lot and all, but it seems too convenient an explanation. Square (before Enix) had another series on the snes called Chrono Trigger and later on the ps1 with Chrono Cross. In it, its realized that timelines that are cut off are not simply cast aside, but rather attempt to fit to mend contradictions in the current time line so that it makes sense. Now, i'm 99.9% sure that won't happen here (you never know) but you have to admit that it is food for thought.