Leaving aside whatever issues there might be in terms of making quality media, we also have a couple of problems in today's society in terms of finding
stuff that is Really Good.
One problem is the inevitable one that if you are looking at media (books, music, movies, whatever) created recently, we haven't yet had the benefit of the time it takes to sift through things historically and pick out whatever was best from a particular era and forget everything else. That is, we know what were the best books from the medieval era because those are the ones that survived the tests of time, but things currently being written have not yet been sifted in that way.
Another problem is that our current society in America (and some other places as well) has hideous tunnel vision and is extremely focused on 1) recent things and 2) whatever is being advertised to us.*
*Side note: I recently read in a book about language learning, written by an Irish person, that he is always being asked his opinion on expensive language courses like Rosetta Stone by, in particular, "Americans overwhelmed by marketing and advertisement campaigns."
So if you want to talk about literature, the number of great writers throughout the world who were devout Christians and wrote masterpieces is pretty overwhelming. You have Dante's Divine Comedy,
Spenser's Faerie Queene,
John Milton, Gerard Manley Hopkins, John Donne, Nathaniel Hawthorne's The Scarlet Letter,
and the great novels by Dostoyevsky. Even in the cases where these authors were not inventing genres or techniques per se, you can definitely not say they are not creative. (BTW, just yesterday I was listening to a lecture by an Orthodox priest in which he said The Brothers Karamazov
is the best theological work outside of the Church Fathers.) Also, all of those writers are not just nominal Christians but people who were very devout and wrote about spiritualtiy because it was important to them. For a contemporary writer, Marilynne Robinson writes incredibly beautiful and skillful and spiritually-informed literary fiction, but no one has heard of her because this kind of literary fiction does not make blockbuster movies or have the kind of appeal that can be mass-marketed.
In terms of music, again, if you look at things historically, just to name a few things, you have all of the Catholic Masses that were written by classical music composers, the entire body of sacred classical music (not just Masses but a ton of other things written for performance in church or otherwise as sacred music), and everything ever written by J.S. Bach, who signed every single piece of music he wrote with "Soli Deo Gloria," which means "To God alone be the glory." If you look at the whole history of classical music, it is not a case of Christians asking, "Why does the devil have all the good music?" it is the opposite, it is a case of "Why do the Christians have all this amazing music?" You can even see this in YouTube comments nowadays; I am always seeing positive comments on sacred music by non-religious people saying things like, "I'm not spiritual, but this is an extremely moving and beautiful piece of music."
Again to name one contemporary figure in art ("classical") music, Arvo Part has been the most-performed living composer in the entire world for the past five years in a row, and people of any and every spirituality and even no spirituality find themselves really resonating with his work, and he is a devout Orthodox Christian whose music is intrinsically informed by his faith. Oh, and on the subject of originality, he also completely invented the musical technique that he is always using, and although other composers have tried to imitate it it fails to create the same sense of spirituality as that in Part's music.
In popular music, there are heaps of Christian bands making music in all sorts of different genres and doing a perfectly good job with those genres, like industrial (Chatterbox and AP2), grunge (Grammatrain), Celtic punk (Ballydowse), synthpop (The Echoing Green), and metal (name a subgenre and I will name a Christian band who does it, though Extol is my all-around favorite), but obscure genres are obscure genres and you cannot expect those bands to become broadly known in society at large.
I won't say as much about movies, since there are those other threads specifically devoted to them, but I have noticed that the Christian films that are well-known and that are marketed are the ones that are typically not regarded as being any good (I haven't seen them but do not have a positive impression about the Left Behind movies and God is Not Dead based on people's comments), but there are other ones out there that are good movies but just not titles that immediately leap to people's minds when they think of "Christian movies" because they are more obscure. For example, Romero, Alfred Hitchcock's I Confess, and The End of the Spear; even some shorter and more obscure things, like The Bridge
(gospel message in allegorical form) and this wordless short made by some Russian seminary
are pretty decent for what they are. But they don't have any marketing behind them, so they aren't on anyone's radar.
I'll leave the issue of what are the society factors that hamper Christians in comptemporary society from making good media for someone else to beat.