Bad luck may have caused Neanderthals' extinction – study
Homo sapien invasion may not have prompted Neanderthals’ demise 40,000 years ago
Perhaps it wasn’t our fault after all: research into the demise of the Neanderthals has found that rather than being outsmarted by Homo sapiens, our burly, thick-browed cousins may have gone extinct through bad luck alone.
The Neanderthal population was so small at the time modern humans arrived in Europe and the Near East that inbreeding and natural fluctuations in birth rates, death rates and sex ratios could have finished them off, the scientists claim.
The findings suggest that the first modern humans to reach Europe were not superior to the Neanderthals, as some accounts argue, and that anyone encumbered by survivors’ guilt may have good reason to unburden themselves.
I think people hamper themselves by seeking "the one true answer that fits all" solution to problems. There were probably different factors involved in different cases. The populations of both HSS and HNS were spread too thinly over a large area to think that one factor was involved in all instances.
Besides, we know through modern genetic studies that HNS lives on in us!