Robert Schoch bases his conclusions on the erosion seen on the base and original area excavated by the original builders of the Sphinx clearing which required a specific amount of water erosion over time to wear away the stone to the depth observed. In addition, Robert Schoch further uses the astronomical placement of both the gaze of the Sphinx and the Sphinx's causeway leading directly to the rising of the constellation Leo, the Lion on specific dates in antiquity as part of his dating of the construction as part of his theory.
Yet Colin Reader rejects all that testing, observation, and architectural placement to claim only a few hundred years of additional age. Ergo, Reader does NOT agree with Robert Schoch at all. If the Sphinx is NOT associated with the construction the Pyramids, then who did build it and why? It bears no relationship architecturally to the style of the pyramids. There is no reason to connect it to the pyramids. There is no evidence at all there was sufficient rain to account for the observed erosion at the time Reader postulates. . . and later the areas eroded were covered by sand.
They seem to omit that R.Temple’s idea is that the erosion was caused by deliberate inundation in ancient times as part of a ritual of rebirth, as I recall. Which is why Temple (an accredited Egyptologist and Science Historian) gives it a more recent date then R. Schoch, a geologist and largely self-taught in archeology.
Temple bases his idea on extensive study of Sphinx - its documented history from the 17th century to present, along with exploration of the the Valley and Sphinx Temples - both of which are either partially explored or the evidence from the 19th Century explorers is ignored. Modern archaeologists ignore both temples believing they are unimportant.