It's important to point out that the temporal rift that caused all this was not generated from the future. It didn't reach back in time and yank the Enterprise
-C forward, it originated in the C's time and PUSHED it forward. It was in that ship's present, as it were. Thus, like I said, there could never be a timeline where the rift didn't occur at all.
If the rift HAD originated in the future - in 2366, where TNG was at that point in the series - then of course there would have been an original timeline with no rift at all. But this is not the case.
Even the episodes of TNG that were made and aired before "Yesterday's Enterprise" - they all took place in a timeline where the Ent-C had returned from the "war future" and sacrificed itself. Anyone in those episodes would of course have no idea what was about to happen, but it still did.
Indeed, it's debatable whether or not the Ent-C could have even done anything in the battle with the Romulans if it didn't make that brief jaunt to alt-2366. Look at how banged up it was when we first saw it...