What you call "the superiority of the Greeks" may simplistically be said to have resulted from two related social processes. (1) Military conquest
which allowed enslavement of others and subsequently (2) leisure time
for chauvinistic males (whilst waited upon by slaves and females) in which they conducted their symposia
and talked and plotted about "higher things".
Modern philosophers (from the well heeled Western world) have even "blamed" our admiration for Greek philosophy for misdirection in epistemological matters. And finally, a political consideration of modern
Greece as something of a "basket case", should tell us something about assigning "democratic success" to "a people".