Why indeed were the Egyptians so obsessed with continuity and permanence? I suppose you could sum up the continuity question with the old adage "if it ain't broke, don't fix it". The ancient Egyptians seemingly had a life that far surpassed what had come before them. With the unification of the upper and lower portions of their land, they had good hunting in the upper portion and extremely fertile lands in the lower portion for agriculture, thanks to the annual flooding of the Nile. On top of that, since they lived near the water, trade was a very profitable venture, and as we all know trade is what makes the world economy flourish.
I feel it is for these reasons that the Egyptians also placed so much emphasis on permanence. Their life must have been so good that they just didn't want to give it up even in death. The ideas they held about their king being a god seemed to lend itself to the orchestration of elaborate tombs which they could live in forever. In the film we watched about the making of the great pyramid, one thing that really stuck in my mind was that when the main character was accepted by the “higher-ups” and was promoted in his job, he had a prideful sense of camaraderie and accomplishment and he stated in a proud manner "I am in the service of the king". Perhaps the Egyptians always wanted to be in service of their godlike king, which could be why they put so much emphasis on the permanence of their life in Egypt.