As I've said, its totally possible that they could have done all this 4500 years ago. Just in the range of years that makes up the margin of error in the assumed dates of Egyptian civilization, they could have undergone enormous technical advances. Again, we went from horse drawn carriages to Ipads in 150 years.
I don't follow the idea that they did it all with stones and copper. Unless it was a civilization that celebrated and encouraged the fostering and nurturing of exhaustive OCD as a way of life, there's no logical reason for them to DOUBLE the time of a project to achieve perfect symmetry, when in half the time they could achieve near enough symmetry to the human eye and move onto the next project. So who ever THEY were, they had to have a technology to cut stones that we at present do not posses. And I can't explain why we've never found any fancy looking space age metal machines that would do that.
Which is why I consider a more ancient society. In fact, given the above facts that all engineers have no issues concluding, it really becomes the archaeologists and Egyptologists that insist on pushing the ancient alien theory. Its implicit from their compulsion to disprove the latter because those are the only 2 choices. Accepting the authority of engineers to make this claim is the only way to see this.
The ones still muddling in the dirt thinking the stones and copper chisels are still valid, have been out grown by a present culture that simply can't abide any longer with the rapid pace of exchange of information across multiple disciplines. They're value died with no wall of ignorance to hide divide and conquer behind. Every new idea now has a billion eyes on it the minute its typed into an assertion, and enjoys no murky gestation period of obscurity among tiny cliques of scholars to afford bad idea's the luxury of the cancerous growth of respect.
But I'm new here. I welcome criticism.