Neanderthal innovation or acculturation: did aliens build the pyramids?

I have a (bad?) habit of making flaky analogies, and they occasionally crop up in my writing as well- generally near the end, and they generally read like a poor attempt at introducing stylistic flair in order to bring an essay to conclusion and leave my reader stroking their chin!

One analogy I used that I'm particularly fond of compared speciation and rainbows.  In another, I compared attitudes towards the debate over the origin of late Neanderthal tool industries to19th century anthropologists' incredulity to New World earthworks and Central and South American pyramids- the Hopewell and Mississippian mounds, for example, were attributed by some anthropologists as having built by an advanced race that was destroyed by the Native American tribes.

This incredulity at the cognitive capacities of the indigenous population associated with the complex material culture is echoed in both instances.  Neanderthals are found essentially with a Chatelperronean backed blade in one hand, and a perforated wolf's tooth in another, and the suggestion immediately arises that Neanderthals attained these skills by acculturating themselves with modern humans, generally because Neanderthals are viewed as having inferior cognitive capabilities.  Why IS that (other than humans are egotistical beings!)? 

It's true this is a possibility, that Neanderthals gained Chatelperronean tool technology from contact with modern humans.  But there is also the possibility that Neanderthals simply developed these tools themselves.  After all, we see examples of Neanderthal symbolism before evidence of modern human arrival such as with the ochre covered shells in Spain 50,000 years ago, uses of black manganese, burial, deep cave use, and complex tools like throwing spears and hafted points, well before Neanderthal use of a 'typically Upper Palaeolithic' toolkit.

As a sister species that branched apart only 4-500,000 years ago, we can expect there to be some cognitive differences between modern humans and neanderthals, but I expect there were also large similarities.  Both species seemed to use technology to adapt to their environments to a large degree, and I do not believe things such as symbolic thought, language, and complex tool manufacture to be out of the realm of the Neanderthal mind.

To me, jumping to a conclusion that if Neanderthals did have complex tool sets resembling what was once thought unique to modern humans then it must have been a borrowed or copied technology, is reminiscent of 19th century anthropologists incredulity that indigenous populations built great momuments and fine architecture.