[simple-thoughts]

Survivorship bias. Buildings with brilliant architects and engineers are more likely to last through history and/or be preserved by their fans. So the expectation would be, when looking at the best products of the past, the average IQ of their producers would be above the average of both their time and ours.

[thriftwy]

Almost everything has survived - I'm living in a city where buildings were mostly preserved indiscriminatingly. They're just that good.