Yea I agree. It was bit odd after playing Golden Sun 2, to see all this civilizations that have supposedly been around since "forever". Like the Alchemy Well, the city of Ayuthay and Passaj, etc. Also the whole back story with adepts and non-adepts working together which wasn't even hinted at in the past games. Although we did know that being an adept wasn't meant to be flaunted (as in, it was supposed to be kept a secret), and how non adepts couldn't see adept powers.
It just felt weird to get all that backstory without any hints in GS1+2, so it looked like all those civilizations just sprouted up in 30 years. Same with the beastmen, where we just saw a single village in GS2 but now they have a whole civilization going on. If they make a remake of GS1+2, I'd want them to atleast hint towards such things to make the progression smoother from the original duology to Dark Dawn.
Anyways, whoever has gotten their hands on Octopath, I hope you enjoy it (I don't have a switch yet) and its sales encourage Nintendo to pursue classical RPG series like Golden Sun instead of just the modern RPGs like Xenoblade.