Well, first of all, Egyptologists don't ascribe to that theory, it's what Schoch, West, and Bauval came up with. Bauval was the first to connect the arrangement of the great pyramids to the arrangement of the stars in Orion's belt. Secondly, Egyptologists don't like it when conventional 'wisdom' is challenged. The site known as Obiados (sp?) is impossible to explain with conventional notions regarding the Giza plateau and whom carved the Sphinx and placed the foundational stones for it and the pyramids.
I don't buy the Orion's Belt hypothesis any more than the layout of the City on Mars. Do you happen to know the story of the origin of the third pyramid, the smaller one?