your first link is for pyramids built at the same time, and gives no indication of timeline.
the second link has the same problems.
also, don't forget that the egyptians started to build tombs w/o the pyramids. such as King Tut's. also, don't forget the temples they built.
here's a timeline of egyptian history.
http://www.wsu.edu:8000/~dee/EGYPT/TIMELINE.HTMTake note that the Great Pyramids (Khufu's) are of the second generation of pyramid building. they did not start off with the greatest--they had a learning curve.
Temples come later, as do the tombs. Some of these are also very complex, such as
Temple of Karnak:
Karnak - Wikipedia
in other words, the biggest piece missing in your puzzle is the timeline. oh, and egypt has something like 80 to 110 pyramidal structures.
finally, as to losing and gaining technology:
this seems to happen many times in history. one need only look at europe and see how much has been lost from the classical era (greek and roman empires) to the medieval ages to now. we lost a lot of technical know-how from the classical to the medieval ages. since about the 1400s (and even more so during the 1600s onward) we've recovered and advanced.
oh, and I love the racism in your post
persons with ultra-intellect (= descendants of Adam)
and
failed attempted copies built by North African sun worshippers
you disgust me.