The story of Christian art is a complicated one, and anyone trying to discover how it came to settle into such a low grade in our present day (although, any time you say this you have to provide a caveat that there are many Christians in every field who are thinking well about their art and producing wonderful work, but they are the exception rather than the rule) has to see it as a combination of many factors. Without a doubt, one key factor that brought us to where we are is Christianity's exile from academia.
To some this might seem like a non-sequitur. What does the world of academia have to do with Christian art? A lot. If you look at general cultural trends in history the pattern emerges that culture is created at the top, and trickles down to the general population. Postmodernism was a subject of philosophy papers 50 years before it was on MTV. In folklore the understanding used to be that the "lore" of the folk arose from the folk themselves, but that isn't the understanding anymore. Now it is believed that the lore, or culture, of a people flows out of a relatively smaller group of social elites and then diffuses into the general population. Wendell Berry, thinking about this from the slightly different angle, said that the country gives the city food and the city gives the country culture. It could be said that academia gives the world its mind.
I make this point to say that academia occupies a powerful post in any culture. There is a sense in which, the thoughts that the academics think, the culture will think. Academics carve out intellectual space which people can live and create in.
One of the reasons why we find little space for Christian art is that there is not space for it in the academy. Religion, as it is commonly portrayed, is seen to rub against the grain of what the academy is about at its most fundamental levels. Science and understanding is about objective fact, testable truth, and knowledge free from the superstition of religion. Religion is seen as undermining knowledge and inquiry, let alone creativity and art. This is an unfortunate mistaken notion.
Christianity has massive resources for careful thinking and careful artistry, but that will not be shown until Christians begin to think and create well. For this reason Christians in academia should be celebrated and supported rather than, as they often are, told to go into the "ministry." Christianity has resources within it to claim Christ's lordship over every inch of life, including the academy.
In this, as in any area of this broken world that we hope to redeem, the fallenness will only be beaten back by God's people entering a place incarnationally and serving it faithfully and creatively. If we hope to reach a culture, we have to go to where the culture is made. Then, perhaps, believers will learn to think well and apply it to their art (and every place God calls them) and the notion of Christian art will begin to change from a marketing scheme to something closer to a fountain of creativity mirroring the infinitely creative one in whose image we are made.
One way this can be achieved is through the development of a Christian aesthetic.
An aesthetic in art, in short, is a way of seeing art, a certain set of questions to ask of a work of art, a set of convictions about what makes good art and what makes bad art. It is a body of ideas that shapes a body of art.
To make an abstract idea more concrete lets take some concrete examples of other aesthetics in the art world. Impressionism, in the history of painting, is an aesthetic. The Impressionists had certain convictions about what made good paintings and what made bad paintings and then took out their canvases and made art in line with those convictions. Paintings made in line with the Impressionistic aesthetic have visible brush strokes, emphasize the changing qualities of light, often choose ordinary things as their subjects. It is a body of work that is all unified by a common body of ideas.
Aesthetics generate art.
An aesthetic is a canopy under which new art can grow. It is a frame which gives a structure for new artists to build on. It is a worldview. And all of our creations are simply products of our worldview. Impressionism was an idea created Impressionistic artists, as people came to share the convictions of the first Impressionists they in turn created Impressionistic art, which in turn fed the cycle all the more. The feminist aesthetic provided the resources for artists to create work in line with the priorities of feminist criticism. And so on. The Black Arts Movement gave rise to Amiri Baraka and Maya Angelou. Ansel Adam's convictions about what made a good landscape photograph spawned a generation of Ansel Adams photographers. There is a reason why every fantasy novel has echoes of The Lord of the Rings. People make creations in line with the ideas that have shaped them.
If there is to be robust Christian art there must be a robust Christian aesthetic. Christian artists must have the resources to come to any work of art and say something about it from a Christian perspective. And this something must go beyond the level of "it doesn't have a clear moral" or "this poem is not about Jesus." Those considerations do not make good art. When there is a thoughtful, informed aesthetic to unify Christian artists there will be thoughtful, informed Christian art.
This is why the question of how Christian art came to be as it is is so complicated. It not only a question of changing the art itself, but of changing the ideas behind the art. It is a question of scholarship and criticism. It is changing the way we answer the question "What makes for good Christian art?" to reflect the depth of Creators creativity and all the powers he has given artists to say something true about this world we find ourselves in. Until we can achieve that good Christian art will be only for those artists who have the wit or luck to figure out what it means for them to be a Christian and an artist on their own.
If this is the fate of Christian art then the Church will leave huge fields of the world God has made barren of the seeds of redemption that may arise when Christian artists pour themselves into the world for the sake of the world's flourishing.