I placed it as such because I assumed it wasn't at the very beginning of Mayan culture, but more likely during the Archaic or Preclassic periods, likely sometime after 2000 BC, maybe even into early centuries of the Common Era/AD.
It's possible it could happen before the events of The Dark World flashbacks but nothing specifically establishes that as being the case, and from a cinematic standpoint it made more sense to place the flashback/prologue portion of TDW first.
Also, Malick mentioned that Alveus/Hive was created "thousands of years ago", and if I recall correctly it was mentioned Hive/Alveus was banished to the planet Maveth "centuries ago", likely not long after he transformed from the Terrigenesis, so it seemed likely his transformation and banishment occurred sometime after the events of TDW based on the dialogue (reconciling the different eras of Mayan civilization and the "thousands/centuries" comments).
It is possible Alveus survived on Earth after his transformation for much longer, but we just don't know for sure. I just figure that Alveus/Hive was transformed (thousands of years ago), rebelled against the Kree and drove them from Earth, and then he was betrayed and banished to Maveth (centuries ago). There's no clear timeline of how long that all occurred, but I find it unlikely Alveus hung around Earth long or else he'd likely have taken over the entire Earth with his mind control. So, it seems likely he was banished not long after his creation and rebellion against the Kree. Thus, both the thousands of years ago (for his creation) and centuries ago (for his banishment to Maveth) make sense by placing those events at most a couple thousand years ago or less. That said I could be wrong, there's no way to know for sure currently.
We know that Asgardians age extremely slowly, so Bor being the leader during The Dark Elves war gives a big gap between the two Thor prologues.
In the prologue with The Frost Giants, we see human settlements and civilization. The Hive flashback shows what could be an early form of man, before civilization. Though that's just an assumption.
Well, we know The Dark World prologue/flashback occurs 5000 years before the present day events, thus we can place it in an exact year of 2988 BC (5000 years before 2013), and the first film's prologue occurs concretely in 965 AD.
Just to clarify the exact placements for those.
