You must remember that many people who write about Ancient Egypt are coming from a background that is totally unfamiliar with the types of 'religious' or cosmological concepts they are researching. They see what they want to see, or as much as they are capable of seeing, no matter how many years they study the subject.If the writing was on the wall and no one could read except the priviledged, then why go to the trouble of encoding knowledge of PI, or show knowledge of planetary orbits in ratios of the size of objects in egyptian art or why encode knowledge of precession in the physical design of the pyramids or any of the other mystical and often ridiculous claims made by people?
That the AE encoded Pi, or knowledge of planetary orbits or knowledge of precession is the kind of thing usually raised by either pseudo egyptologists who WANT to find such complexities in use by the AE in a manner they personally recognise, or by people who have not studied Ancient Egypt remotely and come out with ridiculous suggestions that anyone who has read even half a dozen books on Ancient Egypt would be able to counter.
Yet look at some of the bizarre cosmological systems that have been accepted by science in the last thousand years. If the AE believed certain things at a certain time, they were quite capable of incorporating such ideas into their designs
The Ancient Egyptians had a complex set of mythological texts, and a good Egyptologist will tell you that there is a lot of speculation involved in what has been written and what is still taught about Ancient Egypt. Add to that, that we are talking about a period that covered several millennia, with all of the external influences on the culture etc. and you will see why there are further complications when studying Ancuent Egypt.
Just to give you an example to get your head around the period being covered - I think the most fascinating person in Ancient Egyptian history was one of the sons of Ramesses II. He was not a military Prince, he went into the priesthood and was a renowned scribe, Sem priest and a skilled magician (in the AE sense of the word). He also is credited as the first Egyptologist, because he restored several old temples and pyramid complexes. When he went to see the pyramids, (around 1250 BC or so) they were already thousands of years old.
He revived a lot of 'ancient' customs in his own lifetime - and by the time he revived them, his versions were unlikely to have been identical to those of the Old Kingdom due to the vast amount of time that had passed.
Jaq