aesthetic consistency was certainly more of a thing; today you can find dozens of beautiful buildings in a city but many are beautiful in different ways.

a whole city built in art deco or brutalism for instance could easily look better than palmyra, so its not like people forgot how to make things look nice. cities have just grown fast & art movements change fast so we get smatterings of good in basically every city along with tonnes of shit. places like Paris too have their share of ugly outside of the imperial bits.