Probably a better analogy. As DNA-based anthropology advances, it becomes more and more clear that some as yet undefined metamorphosis happened to the human mind 80,000 or so years ago. The African exodus resulted.

It was closer than I remembered. Quickly re-read the book today - I had forgotten the Ouija scene and the New Athens location. IMHO it would have greatly improved if Ricky/Rikki had left the stage after the first episode, if the silly frozen girlfriend scene never happened and if there was a lot more of Karellan and…

Except there were no human left on earth (except for Milo - his bad) when it was disincorporated.

No, in the book it was made clear that, left to it’s own devices, mankind would have nuked itself out of existence, or so the Overlords claimed.