Monster Hunter is a post-collapse society
The Monster Hunter series isn't an epic waiting to be told, but society rebuilding itself.
I'm not going over the detailed history of the Monster Hunter world, because it doesn't exist. Some wikis have a sort of synopsis about what events happened in what order but, as far as I know, there was never an official chronology of the happenings, everything is just stitched together from environmental clues, item descriptions and, apparently, some lore on Monster Hunter Frontier, the series MMO.
So, why "post-collapse"?
If you go beyond the "aesthetics" of each game, it's noticeable how civilization still seems to be kinda tribal and non-industrialized. There are large and heavy weapons that require brute force to be used, everything seems forged by hand, a lot of places are just made up of small villages or towns, and buildings are made of locally available material. At the same time, you have bowguns and gunlances and airships and sandships and cannons. Overlooking the fact that they all seem to mix in a cool way and definitely don't need any in-depth explanation for this1, the well-done mix-and-match has a reason: there was another civilization before this one.
I won't go out collecting item descriptions to prove my point because, to be honest, that's beside the point. The descriptions are flavors to fill a bit of the world, and the ones with "lore entry" relay information as if talking about a myth, not "factual" history. In any case, here's the general idea: there was, supposedly, an ancient civilization with extremely advanced technology. They used the monsters to harness this technology, exploiting them without thinking too much about it. This civilization was advanced enough to even capture and control Elder Dragons. However, Elder Dragons are intelligent creatures, they were tired of how things were going, and a war started that engulfed the world. In this Ancient Civilization vs. Dragons War, everyone lost: the civilization broke down, and a lot of Dragons perished.
Bear in mind that there wasn't an apocalypse or anything. Both sides were just so exhausted from the attrition that things kinda... just collapsed on themselves, much like what happened with a few civilizations in the real world. Then we have the period where people are just trying to survive and slowly rebuilding, or rediscovering, what existed before. And that's where the Monster Hunter games are set.
And it doesn't matter even one bit in the games. It's just not relevant. But, at least in my opinion, it helps to dress the set and keep it thematically consistent throughout the games, instead of just turning into a random mix of "cool things and concepts that somehow work consistently well". That's why I think the beauty of Monster Hunter is in the details, and I mean it. It is, to be frank, quite awesome, even if not that much noticeable.
Now, one "gameplay" aspect that directly points to the post-collapse is the expeditions on MH4U, where you explore the Everwood.
The Everwood itself is a procedurally generated area made of randomly assorted maps, and you never know what you might find. Sometimes, there's a chance one of the maps will be a ruin, and that ruin will have a mining node, and that mining node will give you a "relic". The relics are nothing more than equipment — be they weapons or armor — with random attributes. You take them to a specific NPC to be polished, and if they are good enough, you can use them in battle.
The thing, though, is that they all look way more technologically advanced than the weapons the smith in town can make, in an "aesthetic" sense. Sometimes, they seem downright futuristic. This would prove that the ruins sometimes seen in the Everwood were part of the ancient civilization, and the hunter just made an archeological discovery.
And, again, none of it matters. It doesn't affect anything one bit. But it's so very cool when you start to notice the small details threading the whole theme together, as it brings consistency to the world, but it's not required to enjoy the game itself. Knowing this is a post-collapse society, though, helps understand better things like the Guild's position regarding "monster poaching" and "research", and how some game mechanics weren't something created just to control the player in a meta way, but something to weave them in, something that has a proper place to exist within that world.
That's why I always tell people to try to enjoy the exploration and preparation phases of a hunt. Despite the marketing always focusing on "fight big monsters as an epic hunter", the game is way more enjoyable when trying to immerse in that world, at least in my opinion. That's also why a lot of the "Monster Hunter clones" fail to live up to their expectations for me: too much focus on fights, too little on everything else.2
Now, if I were to criticize one thing here, it would be the attempt to shoehorn "epic stories" into the franchise. I know that a lot of players like this sort of thing but, for me, it seems to go against the design ethos: the epic story is built as the player progresses through the monsters and gets better at fighting them. If there's a narrative telling you how important you are, it kinda fiddles the "player development arc". This, though, is a whole other thing, and I don't want to start ranting here.
But yeah, the Monster Hunter setting is about society slowly rediscovering and relearning what it forgot while trying to tame a wild world again, just that this time they want to avoid going crazy.
Post-collapse worlds are cool.