The explanation is pretty simple: with sufficient effort and skill, it's possible to produce extraordinary works of precision. You cannot underestimate what people can do with sufficient patience and expertise.
However, each artifact is going to be different, because they're hand-made. If you found half a dozen objects that matched each other to extreme precision, you'd have a more serious case- that's the sort of thing you expect to need machine tools for.
One very good way to debunk this stuff is to look at the best stuff that came out of the Renaissance: we know, for certain, that they weren't carving that stuff with power tools.
There were thousands of vases like this found beneath the bent pyramid.
Here's some still photos and captions: https://www.pbs.org/wgbh/nova/lostempires/obelisk/cutting.ht...
The thing that made Ancient Egypt so special and so historically significant isn't that they had amazing technology. It's that they built a coherent culture, religion, language and government. The vast construction projects they undertook were achievable because they could field massive armies of laborers and keep them provisioned for years. They built these massive structures by dint of having lots of food and secure borders.
He cuts it pretty sharp here. And then shows a technique for smoothing imperfections. Also a lot of the stones weren't actually cut perfectly. Only the ones that were on visible surfaces. The technique was probably slow and laborious, but the Egyptians had huge numbers of workers and they spent years or decades on projects.
I'm not sure what the counterargument even is. If the Sphinx was built using super ancient metal tools, where are they? And how did Egyptians make granite carvings all over their empire over the span of millenia? They obviously knew how. We know it's possible. We just don't know for sure how they specifically did it and maybe never will.
It was only a few years ago that we solved the mystery of Roman concrete.
The pyramids are almost entirely made of limestone. Limestone is around a 3.5 on the mohs hardness scale.
The scale goes up to 10 (diamond).
Granite (king's chamber, sarcophaguses, plugs) is around 6, 6.5.
Guess what's above that? Quartz. AKA your common desert sand.
World of Antiquity has debunked several unchartedx videos, including the supposed spiral striations. https://youtu.be/n_NguZUDku4 https://youtu.be/Wcl82hQr8xc
Archeology and Paleontology have evidence for things millions of years ago, yet do not have evidence for Ancient advanced civilizations.
Many astronomers and physicists have engaged in speculations about extraterrestrial life. They also use some radio telescope time for SETI (search for extraterrestrial intelligence) projects.
The thing that sells me, besides the erosion, is the absolutely astonishing artifacts that were left behind. There is no way I could be convinced that hand-driven bronze tooling was cutting diorite to a precision we would struggle to meet today, carving schists so thin you can see light pass through, absolutely perfect symmetry, and creation of granite stoneware with multivariate surface geometry that we'd be unable to do without a precision-destroying tool change.
I find the tool marks on the partially excavated obelisk in Aswan particularly compelling. It's like they had technology that could scoop granite like warm ice cream.
One person doing somewhat interesting research here and other ancient sites is Ben from Uncharted-X. He brings a lot of first-hand content and analysis of areas many can not access, though it is pretty light on conclusions (probably for the best).
As an example, this geometric analysis of a pre-dynastic vase carved from granite belies the capabilities of a forgotten generation of this planet's inhabitants: https://unsigned.io/log/2023_02_24_Initial_Geometric_Analysi...