I can't believe it needs saying, but if someone tried to pass star wars off as fact then you would have to look and assess how realistic was it, does it conform to known science and maths, can it be verified by other means and also if it was faked how would they do it and how would they cover up it was faked. Well hundreds (probably a few thousand) of people were involved in making it, plenty saw it being filmed, loads made the models for it and the people in it were well known actors from other TV shows and films. Wow, that old man looks just like Alec Guinnes...hang on a minute..... You would expect at least one person involved to come out and not keep the secret. "What, that is not real, I built that part of the set, I have photos" etc.