The idea that mankind could exist with intelligence for a hundred thousand years without developing language, culture, and technology seems add odds with what we observe of man today.That assumes no bumps in the road -- besides intraspecies violence, there are impacts, eruptions, earthquakes, and intraspecies violence brought on by those.
And you are assuming a long period without earthquakes etc is necessary for lamguage and writing to arise (then again it might explain California's retrogression!!). Writing apparently arose pretty much simultaneously in isolated areas despite lots of violence and stress.