I like to pretend Venat actually forgot too, but because of how she is she still turned into Hydaelyn and then remembered us and that Meteion is still alive*. That way it gives more of a feeling that some things are written in stone and meant to happen, rather than happening because we intervened.

*could also explain why Hydaelyn 'chose' to shatter Zodiark, rather than destroying him, cuz she knew he's ironically what kept Meteion from coming back.