No, by no means shall I deny human ingenuity, but probably two Great Pyramids stand outside of all wonders of Ancient civilisation. Ancient Hindoos of Mohenjo Daro and Harappa (sp.?) with all my due respect to really Great Indian culture are not the exclusion from the rule. Although I remember several scolars referring to a clear passage of Mahabharatha (sp.?) where the use of a nuke is described when Pandaws (or their opponents? - don't remember) siedge the city, and then say that such a perfectly burnt brick as that one, which was found among the ruins of Mohenjo Daro (sp.?) migh be the particular result of extreme temperature during the nuclear explosion...
Back to the pyramids... Even in the time of Herodotus and then Plato the Egyptian said that the Great Pyramid was the Khufu's pyramid but they didn't say it was the tomb of Khufu. They simply stated the fact that Khufu was the protector of the Pyramid. But thet mistake of Greeks had remained intact through the ages and nobody even cared to correct it. Colonel Wess who presumably found the cartouche belonging to Khufu (some say, with spelling mistakes belonging to different Kingdoms at the same time) looks like an utter fraud.
I read the material by the link you gave. All scientific-like estimates have serious flaws in logics because they all miss several important criteria: one of them is the fact that there was not hard wood in the whole Egypt to be used as rollers. It, of course, could be imported from Palestina but then you should come up with another great discovery of trade routs on such a huge scale in the time of Great Kingdom that you deserve a special price in archaeology and history! Another objection against long-established estimates is that the constructing of a sand slope is a hell of work by itself and would have required probably half of the mass of the sands of Sakhara.
Why then firslly Snofru, the Khufu's direct ancestor was anable to build a real pyramid at the angle of 52 dergees, and once his first attempt failed ordered building a so called Bent Pyramyd, and only his successor Khufu was able to built a pyramyd that 20 times exceeded the Bent Pyramid. What a breakthrough in construction technicues! And all Menacaur, Khufu's grandson could accomplish is the third Giza pyramid 10 times as smaller that the one of his grandfuther! Technical regress or economic crisis? As for me the economic crisis should be the result of construction of the very first Great Pyramid - on such a scale that it should have inevitably destroyed the Ancient Kingdom! That didn't happen.
Simply sayng that the Egyptians were pretty inventive people is saying nothing. I am trying to think, to find but I don't find explanation lying in the realm of primitive techniques...