Because it was the neanderthal women that brought the extinction of the species by interbreeding with african species and therefore we explain the internal gap in between a hundreds of thousands of years of body intelligence evolution merging with primitive intellect. This is the beginning of unleashed miriad forms and a cognitive built around materialistic dimension. For hundreds of thousands of years neanderthal used only two tools, an obsidian stone which cut though anything and a spear that would act as an extension of their body when hunting. Their bodies were not only strong but were entangled with the intelligence of nature.

https://www.livescience.com/health/genetics/the-mystery-of-the-disappearing-neanderthal-y-chromosome