Life doesn’t change.
Sure the technologies advance and the day-to-day gets easier, but people aren’t fundamentally different from how they were centuries ago.
The same emotions and drives push them on their paths, and the same disappointments sour their spirits.
Persephone tended to her souls like a gardener tends to his or her plants, watching them get born, live and die, forget their experiences and come back to life the next time around, like seeds sprinkled on the ground.
It is human hubris to imagine there is a purpose to this repetitive endeavor. Just like is the case with plants, there is no purpose for them to exist other than to perpetuate themselves. Life wants to continue and slowly evolve.
If there was a greater purpose under Olympus, it was too high for anyone to understand it, and it most likely did not involve building mighty empires and fighting bloody wars, the empty vanities and illusions of power that die with their creators.