I read this obituary about one of America's famous iconographers, Demetrios Dukas, and felt vindicated when I read this quote of his about icons: "It's a great art. It's a religious art, but it prefigures modern art. It has elements of Cubism, Expressionism, it has everything. … It's an art that transcends nationalities and speaks to everyone."
A number of years back I had a show of some icons, religious works in oil, and cityscapes in South Carolina. One person who came out could not understand how I could have religious works and icons in the same show as my cityscapes, because the former are 'realistic' and the latter are very 'abstract'.
I told him on the contrary that the religious art that I do - especially icons - are very abstract, so there was actually a lot of similarity between the pieces. He looked at me as though he didn't understand or agree.
The quote above vindicated me in a sense, because icons especially contain all of the great elements and movements of art: realism, abstraction, Expressionism, Cubism, and more.
I have always seen a great deal of continuity between iconography and the art of the undivided Church and "modern" art. Those who do not simply need to study art and art history a bit more!