Why the Egyptians seem so preoccupied with continuity and permanence?

My theory as to why Egyptian people seemed to be so preoccupied with continuity and permanence is related to their religious attitude. I think Egyptian people believed that their king is god. And I also think that they believed there is life after their death.
Then why did Egyptians started to build the pyramid? I have three ideas for that. The first one is that since they are so much into stars, Egyptians believed that making the pyramid, which is high architecture; let them close to the stars after they died. Stars may have represented heaven for Egyptian people. The second idea is that they built pyramid because they believed in the afterlife and they thought that their spirit can come back to pyramid and they can be close to their king even after their death. My third idea is that Egyptian people wanted to show and prove to the world or a future generation that they were alive in the same century with their god who is their king by making grates architecture. Maybe they were very proud of their self to live in the same world with their god. Those are my ideas. I think there are a thousand of theories of why Egyptians seem so preoccupied with continuity and permanence, but it is still mystery. I still wonder how that many Egyptian people can agree to build such a time consuming, and no practical purpose architecture. How could Egyptian people work for the young king? There are a lot of mysteries of pyramid. But I think the mystery makes pyramid more precious and attract people until now.