The lecture is quite undermined by the amount of typos in the slides, especially when she laughs at the Champollion's name and it is spelled incorrectly there.
"consistent style" over a long period of time happens when you're insular and you have no new influences, censor new ideas. Ancient people built things one way because they thought that was the "right" way, and they'd condemn and cast out anyone who disagreed as a heretic, because they didn't have science, and they thought unorthodox ideas were where misfortune came from. Having a variety -- diversity -- of styles is a good thing. Having one "in" way that *everyone* adheres to and then having *everyone* leave it at the same time is bad, but having a diversity of styles being practiced and enjoyed at the same time... is just intellectually healthy. Don't get all paleo and romanticize ancient civilizations...
it was not at all easy from step pyramid to true pyramid...there are several failed attempts we we see..the famous bend pyramid, the mountain pyramid...the collapsed ones .... it required a lot of hit and trial ... these are big architectural leaps ..and btw...Sneferu after two failed attempts did constructed the FIRST true pyramid ... i hate these fckd up Greek names .. Cheops ... it is "Khufu" Not all rocks are brittle .. try calling someone and asking him to break granite .. Egyptians used granite a lot in the construction