The Reasoning behind The Sundering? (*6.0 Endwalker Spoilers*)

[Ilenya]

There's no proof that Zodiark was a permanent solution, though. It's entirely possible that Meteion could have found and affected it eventually, when her Song was that overpowering.

There was also the potential risk of basically Ra-La-ing themselves as sacrifices to Zodiark, but I find that as a whole unlikely.

[Lersayil]

There's no proof that Zodiark was a permanent solution, though. It's entirely possible that Meteion could have found and affected it eventually, when her Song was that overpowering.

There was also the potential risk of basically Ra-La-ing themselves as sacrifices to Zodiark, but I find that as a whole unlikely.

Its very clear that Zodiark was not a permanent solution, as Meteion herself states she had the long term alternative plan of hastening the heat death of the universe. Still, Zodiark turned out to be a very long term stopgap for her immediate threat, and Venat was fully aware of this before committing to her plan. We know of at least twelve thousand years or so of which we suffered no adverse effects from Meteion.

I think its safe to assume that a fully informed and committed Ancient society would've used this time much more productively to come up with a Meteion countermeasure, given what the Sundered did with that same time (even accounting for Ascian meddling).