What has happened to Vana'diel? (Spoiler)

[Veliaire]

Probably a different dimension. Like how the Ivalice we know from FFT is a different dimension than the Ivalice in FFXIV. Others have mentioned FFXV as well. I actually have a Shantotto minion from that event. It's not the same Vana'diel.

Think of it like a Final Fantasy multiverse.

[Floortank]

Maybe the decision to depict the entire universe as being full of suicide planets wasn't the greatest idea after all.

[Kyousha]

Vana'Diel exists in the same way that FF15 exists with Noctis visiting us through a 'magic portal'.

AKA an excuse to have a crossover.

Also Final Fantasy in general loves to reuse names all the time. FFXIV's Shantotto is not the same person as FFXI's Shantotto.

Basically all of this. If you've played ANY other Final Fantasy game, not only in the mainline numbered series but even the spinoffs, you'll be well aware that Square Enix loves to both re-use people's names AND location names. In FFXII, the airships were the names of common summons. Matoya was in FFXIV but that doesn't mean she's the same Matoya from FF1, and so on.

[Ransom]

Metion didn't report not finding life anywhere, just not finding intelligent life that wasn't dying or already dead. And that was 10,000 years ago. A lot can happen in that span of time, not to mention as others have said, there's no way the Metions visited EVERY planet in the entire universe, or even entire galaxy, in such a short span. They found nothing but ruin on the hundred or so planets they visited and extrapolated an assumption that since they found no exceptions it must be the same everywhere, which was kind of stupid since they DID already have an exception to the rule in Etheria itself and if one exception can exist so can others.

[Floortank]

Metion didn't report not finding life anywhere, just not finding intelligent life that wasn't dying or already dead. And that was 10,000 years ago. A lot can happen in that span of time, not to mention as others have said, there's no way the Metions visited EVERY planet in the entire universe, or even entire galaxy, in such a short span. They found nothing but ruin on the hundred or so planets they visited and extrapolated an assumption that since they found no exceptions it must be the same everywhere, which was kind of stupid since they DID already have an exception to the rule in Etheria itself and if one exception can exist so can others.

The story implies strongly that they went everywhere. Her nest is said to be at the farthest possible point in the universe, at the most distant endpoint. Her entire narrative is that everywhere she looked, she found the same thing. Her story is not "but I didn't look everywhere so maybe..."

[RitsukoSonoda]

The shards are fragments of the source when it was sundered.

The crossovers for FFXV and FFXI etc that brought characters from that game or world over were actual dimension hopping from a multiverse standpoint. The version of Gilgamesh that appeared in the mobile game Final Fantasy Mobius actually broke the 4th wall telling your character about said multiverse referencing hero characters from games throughout the main series and when asked how many stories there were going to be said something like "about 15 not counting spinoffs and side stories."

[Shadotterdan]

Just to reiterate, Shatotto from the black mage quests and relic is not the same as Shantotto. In the later black mage quests where you talk to her, she mentions confusion about the assumption that she has a habit of rhyming as a reference to Shantotto.

Also, technically Vana'Diel is destroyed. That world went through its own kind of sundering when it's mothercrystal was shattered into five pieces, and exists in a kind of less real state because of this. This is more headcanon territory, but it is my theory that that has led to a high degree of instability which is why there is so much in the game that involves other realities like Dynamis, the walk of echoes, Sea, wherever voidwalkers come from, promyvion, the summon crystals, escha, and so on and so forth.

[Iscah]

For anyone played since ARR, you would know that Vana'diel do exist in FF14's timeline and confirmed to be not one of the 14 shard.
This is evident in Black Mage's request line and first Black Mage relic weapon.
During the Black Mage soul stone the soul stone is referred to as "The Gem of Shatotto"

Aside of the point already raised that Shatotto is not Shantotto, the BLM quest line is only evidence that someone called Shatotto once existed in FFXIV's world. It doesn't prove that it's the exact same person once seen in another game.

[Calysto]

Seeing how many assets/designs from XI the reuse every expac ; I'd say Vana'diel is well and will continue to do so for a while

[Jennah]

Considering that the narration seems to confuse "star" with "planet", I wouldn't be so sure that "Meteion explored the Universe" means "Meteion saw absolutely everything"

Not to mention that "Ultima Thule" is a medieval European expression metaphorically meaning "the furthest point from here in existence" - but literally meaning "farthest Scotland"... not exactly the most distant point, yes?