The millenial lack of great art, literature, music....more fallout from secularism.
The artists that created longago church art were surely informed by the prevalent religious culture of the time.
When I was stationed in Korea our Chaplain asked me to give a guest lecture regarding the signs and symbols of Christian art. As the class was for GI's I started by presenting them with the Hangul word for "Stop", in plain black letters on a white background. None of them knew what it was, and I established that, w/ regards to Hangul, they were essentially illiterate. As soon as the word was placed in white letters on a red octagon, they knew what it meant...not only did they know what it stood for, but I advised that that simple image was powerful enough that, given a car, it would evoke an internalized physical response...Just imagine the power of images over an entire population that is generally illiterate!!