well, that dating certainly comports with the hard facts of human recorded history as we know it...yes there is a whole industry of “prehistory” but really, it all gets pretty fuzzy (understatement) about 4,000 BC. About 4,000 BC it seems like all of a sudden, we can start to see what is happening out there in the world, from a historical perspective, in terms of human action.
The Basic Non Evolution of Modern Man in case you might have missed it... More than usually interesting is Gunnar Heinsohn's claim of no evidence for Neanderthals which can be legitimately dated to anything further than about 4000 years back.