You do realize the sum of interior angles for any quadrilateral is 360 degrees, regardless of it being "perfect."
And you are implying these angles are perfect to a molecular level?
Source, please.
Consider the construction methods of the pyramids revolved around basic geometry, astronomy, and water levels, it really isn't difficult to reproduce them to an even more exacting standard.
Additionally, the engineering prowess required to build something like the Burj Khalifa is far more complicated than processing raw stone and moving it. The only reason why don't recreate the pyramids is there is no financial reason to recreate them. The reason it was possibly back then is the creative use of ramps and slave labor, the latter being a huge part of it.