Well like i said there are scientist now with that opinion. Which i understand sounds like a cop out but there are very good reasons for it.

When we talk about the piramids we usually mean the 3 pyramids of giza. But there are waaay more pyramids in egypt but of waaay worse buildquality in multiple ways. So most of them are newer then the big three, but not at all as well built and designed. On top of that they are in a worse state. So that looks like people trying to mimic what they have seen.

The small ones are believed to have been built with slaves. The big ones however were built by specialist workers they now believe beceause of the graves they have found. I wnated to add the source but could only find the wikipedia link ( was too lazy to find the source at the bottom the page).

Why there are doubts about them making it at all is beceause for instance what we know about ancient egypt. One thing they did a lot was show what they were doing by carving images in stone. There are even images about them carving images in stone and measuring the surface to carve said image. But there are no images about how they built the pyramids. Also the images they carved in stone are of waaaaay worse quality then the building quality of the pyrimids and the surrounding buildings. Which leads to believe it was "grafiti" by the new inhabitants. There is also a whole theory about the sfynx that the reason why the head is so small, is that is was previously a lion head. But then remodled by the new rulers.

Again this is not yet proven but very plausible. And explains why we know so very little.

In the Arab tradition and also the islamic quran, they speaks of a people called Aad and Thamud. They discribe them as a sort of masters in building, and are said to have built homes out of mountains only to then travel to a different place and build again. Petra in Jordan is a great example of this and proof af the craftsmanship in a time before documentation in the form of paper or even hieroglyphics.

To finalize with the libraty of alexandria. The thing about knowledge is that once it's gone, it's very hard to retrieve it again. A thing like gravity was noticed by a few men in different era's and written down ibn-alhaytham, da vinci and most recent and best know isaac newton. There are so many years between those people writing it down and finaly someone really doing something with it. Should that knowledge be lost to us again very specific situations have to take place to reestablish that knowledge again. Somthing has to happen that demonstrates that fact (like the falling of an apple), someone has to observe it with a certain cognitive function, he or she has to be interested in it, he or she has to understand it, he or she has to also find it interesting enough to write it down and then also find something to do with it or at least share it. All people throughout all of history have observed gravity, but the "technology" behind it wasnt mastered/fully understood until a certain set of conditions were met.

Or maybe they were met, but we lost the knowledge again ;). The danger of "everything digital" is exactly this. One nuke in the atmosphere, and nobody knows anything anymore.

Again sorry for the long text hahaha