With all the race problems we face today imagine how fucked up things would be were there to exist one or two intellectually inferior species of hominid.
John Thornton
^^^^
I agree on that the current world culture needs to develop a lot before it could handle two hominid species at the same time.
However, Neanderthal skulls are bigger than homo sapiens, so the individuals might have been smarter. I'm hypothesizing that homo sapiens individuals were less smart than Neanderthals , and may have relied on kinship and social connections more than Neanderthals because of that. This higher social quotient is how the homo sapiens were more fit than the Neanderthals. The idea is the Neanderthal individuals were so smart , they could survive as individuals better ( Robinson Crusoes), but then individualism was less fit relative to the high sociality of the homo sapiens ( us )in the long run.
Charles