This camel rock carving dates back 6000 years or more.

https://www.bbc.com/news/world-middle-east-58570259

Which makes the argument of the Sphinx less compelling.

We can directly date the burial of granite objects with OSL. We can detect human populations with charcoal, pollen analysis, modern genetic studies, or directly with eDNA (among others).

But still that only tells us when those granite artifacts were last used. In some cases they might have been constructed much earlier, and then reused or modified by later civilizations.

Yes, which is why there's a whole network of independent lines of evidence that inform modern consensus. Our picture of the neolithic, while still incomplete, is complete enough that most of the speculation in this thread is pretty unlikely.

I think the pace of new discoveries in that time period over the last 10 years brings into question how accurate our consensus is. The consensus view is the best informed by current evidence, however we lack sufficient evidence to really pin down what humans were doing in most of the world. Given this lack of evidence, our default assumption is that they were doing what they had done before... which was probably living in nomadic tribes ... until suddenly Mesopotamia/Egypt.

So for context, I used to work on this professionally. I still keep up with the literature to a reasonable degree.

The major new tool we have is ancient DNA and the results we've gotten from it broadly rule out most of the 'expected' ways we'd see an advanced, ancient society.

As for that default, most archaeologists would not agree with what you've described. Everyone can point to cultures like the natufians as pre-YD societies that weren't fully nomadic and you can trace that stuff to through the Holocene and later 'civilizations' like Egypt and mesopotamia. Most archaeologists are also open to the idea that there was a tremendous amount of social and political diversity in the late pleistocene that isn't fully apparent in the material record, but this is more of a widespread hunch that doesn't yet have enough evidence to be called consensus.

These days when academics (regardless whether it's public health or archeology) talk about evidence, I tend to read "evidence" as "what we already know", and the whole narrative ends up being "we know what we already know, and we reject what we don't already know".

I mean, there's no way to un-see this way of reading "evidence" after realizing how much humanity has yet to learn, yet there's a class of people who's confident that they're really knowledgable about stuff.

Like the cyclopean ruins throughout Europe that no cultures can lay claim to.

I'd never heard of this; thank you for the interesting topic!

OSL establishes a lower bound on age. Numerous events can lead it to read younger than the reality.

Yet, the Valley Temple and Menkaure pyramid come out 500 years older than the official numbers. (With wide error bars, it must be said.)

OSL can read both younger and older than the true age, depending on the error sources. Modern labs will usually apply a correction to deal with underestimation as well.

Maybe explain how OSL can establish an upper bound on age? It looks impossible to me, except where you can prove the sample was undisturbed.