I agree that we likely have a skewed view of ancient societies from the limited evidence they leave behind. For one thing, we're liable to presume that because they had certain laws, they tended to live up to them. Does the American legal code give an accurate picture of American life, even when the plutocrats find loopholes to get around those laws or to get off at trial? Not all our actions leave footprints for archeologists to find.
I agree also that the Whig, progressive theory of history is nonsense. This is why I don't dismiss the perennial philosophy or the Axial Age spiritual insights, and it's why I criticize many aspects of late-modern secularism.
Still, I do try to decipher the big picture historical developments. The ancients likely had to be pragmatic because their margin of error was narrower. We've built up a greater cushion with our technological advances, which is liable to make us more decadent and infantile. I'd also emphasize the break between premodern and postmodern. The modernist revolutions led to a hyperskeptical overview which wasn't as easily supported in the ancient world.