As the Grand Gallery is an integral part of a passage system with (for the most part) a single North-South axis, one has to ask the same, and at the same time, about the Descending Passage, the Subterranean Passage, the Blind Passage, the Ascending Passage, the Queen's Chamber Passage, the First Horizontal Passage, the Antechamber and the Second Horizontal Passage. Then I think we have to look at a) the rectangular King’s Chamber being orientated North-South-East-West b) the Chamber’s doorway being at the east end of the Chamber’s north wall and c) the sarcophagus being at the western end of the chamber.
I suspect it all has something to do with the North Star, the sun setting in the West and AE religious beliefs.
For what it is worth, I see the Grand Gallery as little more than an enlarged Ascending Passage that served no practical purpose –when it comes to the Great Pyramid of Giza, in my view symbolism reigns supreme.
You have attributed allot of names to all of those passages and open areas. You may be right. I look at it with an open mind. I try my best not to come to conclusions, as I fear that would only limit my thinking. Rather, I look for anomalies. Some feature which may shed light on it's construction. The topic is lost building technology.