Pokopia teased in Arceus?
I've gotten to the end of the game and was looking into the old verses and a lot of Old Verse #20 sounds like what happened to start Pokopia.
"Once it shone upon us all, with all the warmth of welcome sun. "But now we weep, to grief we fall, starved of light now it has gone. "And some they go, despair withal, in search of it they reel and run. "They quit their hearths, abandon hall, and leave our lands to be undone. "And when they're gone beyond recall, this land will be a home to none. This land will only ever be a home to Pokémon."
>!The humans leaving the planet, nature taking back over to make it habitable again, and pokemon slowly coming back into a world inhabited solely by them. It really lines up together in my head, but it might just be me!<