My theory is that line of sight to the temple at Heliopolis was an important factor determining pyramid placement, which therefore dictated necessary height requirements for each pyramid. You'll note, for example, that Menkaures is offset from Khafre's just enough that at its current height it peeks over Khafre's edge to allow line of sight to ancient On. The hill in question would hamper line of sight and thus force changes in pyramid height which could prove the theory.
Later Sun Temples, according to my theory, were introduced to serve as substitutes which released the builders of the line of sight constraints.
Edited 1 time(s). Last edit at 11/16/2017 07:41AM by Pete Vanderzwet.