Starlight Glimmer time traveling shenanigans still had one after effect...one that would ultimately decide Equestria's ultimate fate...mainly because of the concept of a stable time loop and the fact that Equestria's intelligence network is better that other aspects of it's military.

After all, who ever said Twilight's destiny was decided by Celestia...

A little dive into my headcannon and my look at the Season 5 finale.