Why does no one remember Dalamud?

[Tahli]

The simplest explanation is just that it's rarely relevant.

Maybe. It'd be a nice bit of immersive world building if they did include it more though. Even just like a random storefront with a sign that has a picture of the moon on it, with a smaller moon next to it.

[Masekase_Hurricane]

"Miounne: Even now, the wounds have barely begun to heal. Ah, but I speak of it as if you were there. Forgive me. Five years past, Eorzea was well-nigh laid to waste when a dread wyrm emerged from within the lesser moon, Dalamud, and rained fire upon the realm. It is this which people call “the Calamity.”
Miounne: Scarcely a square malm of the Twelveswood was spared the devastation. Yet despite the forest's extensive wounds, not a soul among us can recall precisely how it all happened.
Miounne: I am well aware of how improbable that must sound to an outsider... It is improbable. But it's also true. For reasons we can ill explain, the facts surrounding the Calamity are shrouded in mystery. There are as many versions of events as there are people willing to recount them.
Miounne: Yet amidst the hazy recollections and conflicting accounts, all agree on one thing: that Eorzea was saved from certain doom by a band of valiant adventurers.
Miounne: Whatever else we've misremembered, none of us have forgotten the heroes who risked life and limb for the sake of the realm. And yet...whenever we try to say their names, the words die upon our lips."

Maybe they just don't remember there ever being two moons?

[MikkoAkure]

Maybe they just don't remember there ever being two moons?

Astrologians remember. It’s even mentioned that they still take into account where Dalamud would be for their calculations and readings.

[Alenore]

Because there's only so much text writers can put in quests and dialogs, and they'd rather use that place for stuff relevant to this expansion rather than content from over 10 years ago.
You probably realize what you see on screen isn't the full extent of our interactions with NPCs we would have this conversation with. But it would be kinda weird to speak to a new NPC and he casually drops "wow btw the moon was super big for a time, crazy huh?".

[PorxiesRCute]

Because there's only so much text writers can put in quests and dialogs, and they'd rather use that place for stuff relevant to this expansion rather than content from over 10 years ago.
You probably realize what you see on screen isn't the full extent of our interactions with NPCs we would have this conversation with. But it would be kinda weird to speak to a new NPC and he casually drops "wow btw the moon was super big for a time, crazy huh?".

Good thing this thread isn't about people not talking about when Dalamud fell. But some people here seem to think Dalamud sprang into existence only to then immediately fall out of the sky.

I'm talking about stuff like how the Xaela have an extensive sun god/moon goddess myth but with no mention of the other moon that was in the sky for thousands of years. No casual remarks about how timekeeping may have changed with there being only one moon in the sky. MikkoAkure mentions astrologians taking Dalamud's projected location into account, and that's an excellent example of a little thing that makes sense in the setting! It was also way back in Heavensward (if not ARR; I don't actually recall seeing it myself).

[MikkoAkure]

Good thing this thread isn't about people not talking about when Dalamud fell. But some people here seem to think Dalamud sprang into existence only to then immediately fall out of the sky.

One thing to take into account here is that in the grand scheme of things, Dalamud was never particularly large in the sky or terribly prominent. This was never a "there's two whole moons in the sky, this is so fantasy!" situation in this game. In earliest 1.0, it was a little bit bigger and brighter than say Venus is viewed from earth and barely larger than the stars around it. It was more of an accent to the real moon like a tiny little mole hanging off the side than a second full-sized moon like a lot of you seem to insinuate.

Think of the 6 different colored stars in the sky in-game and that’s what Dalamud was like, being the of similar size, except that it was only around the moon. We don’t exactly hear about what different cultures think of the giant green star in the sky outside the AST quests.

[LilimoLimomo]

There used to be two moons in the sky. One Xaela tribe, the Dalamiq, is said to worship Dalamud. We never see them in-game. Otherwise, everyone on the Steppe talks a lot about the sun and the singular moon.

How is it the second moon that existed until only five (canonical) years ago has had zero impact on Hingan, Yanxian, Hannish, and Turali culture?

You've got a good point. I wouldn't expect there to be constant discussion of the red moon, but it would have presumably been part of the culture of any culture revering other heavenly bodies.

All of that said, I think the answer is obvious: understandable oversights were made with the writing and world-building. It certainly isn't the first time, certainly isn't the most impactful time, and it certainly won't be the last time.

[Cleretic]

One thing to take into account here is that in the grand scheme of things, Dalamud was never particularly large in the sky or terribly prominent. This was never a "there's two whole moons in the sky, this is so fantasy!" situation in this game. In earliest 1.0, it was a little bit bigger and brighter than say Venus is viewed from earth and barely larger than the stars around it. It was more of an accent to the real moon like a tiny little mole hanging off the side than a second full-sized moon like a lot of you seem to insinuate.

Think of the 6 different colored stars in the sky in-game and that’s what Dalamud was like, being the of similar size, except that it was only around the moon. We don’t exactly hear about what different cultures think of the giant green star in the sky outside the AST quests.

So perhaps the reason the Azim Steppe doesn't talk about Dalamud is because they didn't really think of Dalamud as a moon. It was on a scientific definitional level, and Menphina's faith called it a moon, but who says anyone else did? When it was up there it didn't necessarily look like one. Just like how Earth has plenty of moons, but also only really has one moon.

Maybe the only reason Eorzean faiths and knowledge called it a moon was because that was just a lingering relic of Allagan knowledge.

[Turnintino]

For clarity, this is what it looked like before it began to fall:

[No_Nick_Needed]

A lot of art and culture does revolve around the natural world that they see around them, though. There are obvious ones like Keeper of the Moon Miqo'te. Even aside from that, you would think to see depictions of it just as much as the larger moon still in the sky, no?

Speaking of the Miqo'te and moon; It's a pretty funny conincidence that the Moon Miqo'te are called Keepers, when both moons were prisons, one for Bahamut and the other for Zodiark. Unless of course that bit was planned from the very start of 1.0 and it was intentional.
It almost sounds like the Keepers of the Moon were once involved with guarding either Bahamut's or Zodiark's prison.

Anyway, in the Endwalker Alliance Raids we learn that the followers fo the Twelve acknowledged Dalamud so much, that their prayers made Menphina spawn an entire giant wolf from that believe, so yeah, it would make sense for other cultures over on Tural or Orthand to have some similar myths too.
Maybe we'll get that once we go to Merasidia, however many expansion in the future.