No, I did not say that Neanderthals were our ancestors, but that we had a common ancestor. Experts agree that Neaderthals and Homo Sapiens could even inter-breed, as they were so genetically closely matched. We evolved from a common ancestor and we survived, while Neanderthals were either a evolutionary dead end, or they inter-bred with Homo Sapeins until their species was gone.
As for your gorilla example, show me a gorilla species that makes fire and buries it's dead.