Would a civilization that is really thousands of years old need the assistance of a foreign man born at the beginning of the 20th century to carry her reputation?

I guess the answer is that we (people in general) do need academics and scholars who devote their lives to researching a particular field to help us understand such things because of course we are not born with an inherent knowledge of everything. Whether we choose to accept these academics conclusions is another question but you can't question their usefulness to the debate as a whole. I could pose a similar question asking whether if evolution is such an obvious scientific fact and has been in evidence for billions of years did we really need some naturalist from Shropshire to come along and point it out to us? Like Darwin many of Needham's theories have been challenged, amended, expanded or rejected entirely but we did need him to at least bring those ideas to the fore so that they could be given consideration in the first place.