Shermer was literally a minor-Christion sect cultist before becoming skeptical(tm).
Remember that to the masses, 'science' is simply modern magic. Few understand how their phones actually work, the physical laws of the universe, and real history. They don't even understand the difference between a Scientist and an Engineer. They are all Wizards to them as far as they are concerned, and they worship them as authority figures and as proof of their ideology just as barbarians of the past would worship idols as gods themselves.
His imagination may often get the better of him. Wouldn't it be the best kind of story if Atlantis and Mu and all the ancient legends were actually true in some sense? That is so exciting that when a scrap of potential seems to point that way, Graham declares it most likely is true! He's getting a bit ahead of himself with his fascination, but the evidence of ash-layers, water erosion beneath the Sphinx, and relief artwork on stone megaliths implies something of intelligent humans beyond mere hunter-gatherer types before 12,000 years ago.
'Historical Progress' is not necessarily refuted by this because the idea still present in your observation would be, "we are getting worse, not better." It still implies movement on a singular measure of 'progress'. For instance, was it 'progress' to go from the oral tradition to the written? On the level of information dispersal and physical preservation it is superior due to idea becoming independent of human minds, but on the level of idea cohesion and human memory it is inferior due to human minds no longer bearing that burden and thus weakening. We may have a metric that we want to improve like IQ or racial purity, but this is not 'progress' as it is evolution because the whole is simply something different rather than a unified 'better'. Thus 'Progress is a myth that implies a trajectory of history towards whatever end the bearer thinks, like a bland world without war, famine, death, or suffering. We are almost all afflicted by the reason of 'progress' just as we are very much infected with ideas of Utilitarianism and so forth. The Ubermenche has to take these ideas and reconstruct them into a new form, not 'progressing' but changing it into a more suitable form. It is fundamentally human to oppose 'progress' in favor of evolving himself and his domain.
As you should be. Aquatic Ape theory better explains our mostly hairless bodies to be hydrodynamic, upright posture to allow us to collect shoreline foods and resources, the wrinkling of out fingertips while underwater being a built-in reflex, the fact that humans can not only give birth in water but that newborns automatically swim and hold their breath, and our universal preference for a temperature that a semi-tropical shoreline would afford. But yes, it is a topic waaaaaay before the scope of this conversation.
Another interesting take on creation myths is the Greek version where humans are not actually the center of creation at all, but a novelty originally constructed by Prometheus to amuse the Gods. But Prometheus pitied the humans because they, being similar to the gods yet moral, suffered horribly while the other animals didn't, and so stole fire from the gods to give to humanity who took to it and began acting like the gods themselves in quick order. That got Prometheus eternally punished and Zeus tried to drown humanity before calming down and enjoying their worship and getting interested in their affairs instead. Notice that the gods whom the Greeks worshipped didn't create them, that their creator was dominated by them and didn't dominate his creations at all, and that there is no good or evil involved as understood by the Semetic stories. Greeks didn't bow when they praised to their gods either an absurdity if you think about a tiny human lowering himself to a god out of 'respect', like a worm flattening itself before a mountain so as not to be perceived as haughty, which was in part why they refused to submit to Xerxes and other Eastern god-kings. Yep, that's Nietzsche's observations about the poison of the Jewish tradition and its slave morality.