The reason people resist the idea of super-advanced ancient civilizations is because, quite simply, it fails Occam&#x27;s Razor hard. The strongest evidence for such an idea is rooted in anthropological evidence, which is among the weakest historical evidence you can produce. There is instead a noticeable lack of evidence in the form of concrete archaeological evidence (it should be noted that it&#x27;s possible even to see signs where wooden or earthen structures once existed, if you know what you&#x27;re looking for) or suggestive genetic or biological evidence. It&#x27;s also well-known that technological progress is in no sense inexorable--the Chinese printing or Roman steam engines went absolutely nowhere, for example, and even the bow-and-arrow was lost by some aboriginal tribes for unclear reasons.<p>It is certainly more plausible to suggest that human populations were too thin and nomadic to sustain technological innovation prior to the development of the sedentary lifestyle that arose during the Neolithic Revolution (itself caused probably either by some sort of climate change or overpopulation).<p>I should also point out that your view that larger cranial capacity early on means that humans had to develop civilization earlier has an uphill battle to explain why modern humans are Homo sapiens and not Homo neanderthalis (who had a larger cranial capacity than Homo sapiens and were probably even more physically fit).