The Inca Royal Family was the architech behind the great Inca Empire not the Quechua or the Aymara or their descendants. A member of that family from a time the empire still existed tells us that unlike their subjects, they are not Native Americans. He tells us this in one of our own languages (Spanish), and phrases his words so that we can tell he understands racial differences.

A modern Archeologist or Physical Anthropologist is not likely to back up his claim, because at any one time there were far less members of the Inca Royal Family than Inca subjects, providing the modern investigator with little or no physical evidence of the separate existence of the Royal Incas.  The modern Cultural Anthropologist is studying the descendants of the construction workers, descendants who wish to take total credit for the building, including its design.  That quipu he has just learned to master bears a closer resemblance to a Chinese Abacus, than a modern Corporate Balance Sheet resembles a Desktop Calculator, but he is likely to ignore the similarity because it does not fit what his informants are teaching him about their ancestors, who were not Chinese.