If people could comment on the origin of the royal cubit and such instead of getting into some ideological arguments about Pharaoh's tombs, etc...
The small Pyramids from the early 5th Dynasty onward were, from all evidence and from the Pyramid Texts, built as tombs of the respective Kings of Egypt as relevant to these Kings' association to the death and resurrection of Osiris.
The Pyramids of Giza, built during the reigns of Khufu (2573 BC – 2540 BC), Khafre (2529 BC – 2505 BC) and Menkaure (2500 BC – c.2482 BC) were built as the Tombs of Osiris, i.e., to monumentalize the end of the first Sothic Cycle in its four sub-forms and in its 1460-year schematic Sothic completion. Built at specific locations: complexes built from north to south, in accord with the decreasing latitude of the Tropic of Cancer, and to the measures of the Tropic's ground-travel.
Whether or not Khufu, Khafre and Menkaure were entombed in the Pyramids (built to the Heliopolitan Priesthood's designs during their reigns) whose names they bear is entirely possible – but that is not relevant to the reasons for their constructions, the lengthening cubit values of their architecture, or for the abstract features, sizes or locations chosen for these Pyramids. (See Petrie 1883:179 for his estimates of the increasing cubit-lengths employed).
Djedjefre did not build a Pyramid at Giza since his reign (2540 BC – 2529 BC) fell between the 1424-year Sidereal completion of the Sothic Cycle in 2552 BC, marked by the lat. center of the Khufu structure, and the true Sothic completion of the Cycle in 2519 BC, marked by the lat. center of the Khafre Pyramid – their resolutions with the revolving New Year's Day of the Egyptian Civil calendar, from their common outset on the first I Akhet 1: the first New Year's Day of the Egyptian calendar determined by the heliacal rising of Sirius over Heliopolis on July 17, 3976 BC.
The Menkaure complex marked the resolution of the Seasonal years with I Akhet 1 of the Egyptian Civil calendar, reason why the Menkaure was cased a quarter high with granite: since mean seasonal time is quadripartite, composed of two equinoctial and two solstitial years.
The unified plan of Giza, of the resurrection of Osiris to Horus, i.e., the death and rebirth of the first Sothic Cycle, was completed by the statue of the Sphinx, whose face represents the Goddess Aset / Isis, at the rebirth of Osiris as Horus, a statue built at its particular lat. location at the birth of a second Sothic Cycle, as relevant to the position of the Tropic then.
It is the cubit values employed in Pyramids of the Old Kingdom which relate their exact chronologies. Cubit lengths derived from a twentieth part of the slowly accelerating latitudinal decrease to the latitude of the Tropic, from the 'Stride of Re', the seminal measure of these Pyramids' designs. Hence, since one now knows the historical rate of annual decrease to the position of the Tropic, the cubit-lengths employed (x 20) relate when each Pyramid was built.
For the Meidum, this shows the (E1) Pyramid was begun in 2621 BC, during the reign of Huni, and (E3) completed in 2576 BC, towards the end of the reign of Sneferu. For the Bent Pyramid, the base length consisted of 363 cubits, which shows the 'bend' was pre-planned, since the upper base-length was designed to 237 cubits, for a total of 600 cubits or 30 average Strides of Re-length in the mid-year of its 2597 BC – 2587 BC construction-era.
The Pyramids of Huni and Sneferu were built as prototype structures, "to assess the speed and logistics at which such structures could be built as well as to experiment in full scale with differing designs to test and refine the structural plans for the Giza Pyramids" – which had long been planned for the Giza Plateau.