Is there a name for the trope where a story is high fantasy at first glance, except for it's not fantasy and is actually set in a post-apocalypse dystopian future?
I'm embarrassed to say that I have encountered this, this particular type of story on multiple occasions... So I got curious, is there a name to this trope?
The Elder Scrolls. It's not explicitly stated, but iirc it's highly suggested it's post-apocalyptic. That said, it's still fantasy, there's still magic, spellcasting and so forth (there's no indication that the magic is the result of lost tech becoming indistinguishable from magic); it's just that the lore highly suggests it may be post-apocalyptic.
It actually doesn't have anything to do with that theory, but I won't lie, I do like that one.
I wrote a bit about it in response to their question, and I think I misspoke (miswrote?) and kinda jumped the gun. It's not really post- apocalyptic, however the series does seem to document a world in decline.
I'm not sure if you'd consider that apocalyptic (a slow apocalypse), heading towards the apocalypse (what happens if all the Towers are destroyed?), or post-apocalyptic (it seems like the races peaked before any of the games) though.
Edit: I remember why I thought it was post-apocalyptic! Space! Iirc all the races have been to space and had spaceships and space battles, except it seems like everyone has forgotten about it by the time the games take place. Combine that with the destruction of the Towers, and yeah. Seems possible that the Elder Scrolls could be post-apocalypse and is being interpreted as fantasy because the characters of the series don't know how any of the tech works anymore.
Oh wait, do you mean on the post apocalypse idea? Ehhhh I'm not certain it is. There is a creation story, and then a "do over" in the lore. But nothing like our civ level in the past for it.
There's probably a lore video about it on YouTube somewhere though.
It's been a long-ass time and some of the lore may have been retconned/clarified since then, however it was a conclusion I came to on my own. Basically, iirc, the Towers are hybrid physical/metaphysical structures which essentially keep Mundus (Nirn + other planes) stable and allow for things like magic to occur. When a tower is destroyed, Mundus becomes less stable and magical ability declines. Let's hope we don't destroy any towers then!
Oh wait. A bunch of the towers (are speculated to be) destroyed. Red Mountain (vvardenfell) was destroyed after the false-god Vivec lost his powers and could no longer keep the Ministry of Truth from smashing into the mountain, Walk-Brass zero-summed itself and the race that created it, the White-Gold tower was destroyed during the Oblivion Crisis, I don't remember what happened to Crystal-Like-Law but I'm pretty sure that's gone too.
If you wanted to get fancy with it, you could even point to the magic system getting less complex with each mainline game (yes, I know it's probably just laziness, but I like my explanation more). Hell, it seems like all the crazy, cool stuff happened long before the events of any of the games; it seems like all the races peaked before we ever got a glimpse into that universe.
So while I guess it's a bit premature to call TES post-apocalyptic, it's definitely headed in that direction. It seems to be a series about a world that's slowly collapsing and falling apart.
Edit: I spent some time trying to brush up on my TES lore (fuck, I'm starting to hear the games' siren song; it's been years), and came across this wonderful paragraph:
Using his dentition as tonal instruments, Anumaril dismantled his bones and built of them a Mundus-machine that mirrored Nirn and its planets. And when he had used all his substance in fangling this orrery, the Orrery of Elden Root, he placed the segment-sceptre within, hiding it between the Moons.
You... you did what?
I wish the games were half as interesting as the lore.
Edit 2: I remember why I thought it was post-apocalyptic! Space! Iirc all the races have been to space and had spaceships and space battles, except it seems like everyone has forgotten about it by the time the games take place. Combined with the gradual destruction of the Towers, it seems possible that the games could be post-apocalyptic but are being filtered through a lens of ignorance, making the residual advanced tech appear as though it's magic.