I know that for many Christians, the dream is to go back to the "good old days" where Christians were "cultural leaders." The dream is to change the culture, somehow, back to where it was in our idealized minds so that the world will presumably be a better place (in any number of ways, depending on what our pet issue is at the moment).
Here's my take on that... I think I'll let God worry about if Christianity becomes the "cultural leader" again. I have zero interest in trying to prove how Christianity and Christians can be "relevant" again or leaders in certain spheres of culture, such as the arts. And after all, the Christian faith is relevant. If I am trying to prove it to people, then maybe I'm not convinced it is really relevant, myself. Maybe I'm the one who is out of touch with its relevance to real life, and if I were more in touch with it I would simply live it rather than trying to prove it.
What would be wonderful is if Christians simply wanted to excel at things because those things are amazing gifts to be cherished and adored. What would be wonderful is if we gave up this ridiculous, "I'm going to prove that Christians can do it well, too" thing. Trust me. People actually care way less about that than we do, and the more we care about it, the more outsiders are annoyed with our sectarian drive to promote our own tribe only.
Besides, I'm not sure having Christians as cultural leaders would necessarily make everything all better. If anyone is a serious student of history, human nature, or religious history, they will recognize the fact that sometimes the most well-meaning of "faith-motivated" ideas turn, over time, into vehicles for oppression and division. It is not just secularism and other "isms" we need to worry about. It is ourselves. The Bible is unique in that it contains the most exhaustive, deep, accurate, and staggering critiques of our own faith compared to anything else out there. We need to heed it. Even if we do wind up contributing many positive things, Christians are just as capable of running the culture into the toilet as anyone else, just in a different and less obvious way.
This is why I suggest letting God worry about those things. Just do what you need to do, and do it well. If you are a Christian film-maker, just make a good movie. If you are a Christian author, just write a good book -it doesn't even have to be a "Christian" book (I know, shocking).
Has it dawned on any of us that perhaps the very thing that today's culture rebels against and rejects most about Christianity and a Christian worldview is our die-hard drive to take over and make things go back to how they were? And that is interesting because, while there is certainly an essential place for speaking truth and speaking our minds, I don't get the impression that the early church was endeavoring to take over anything or gain footing in any way. I could be wrong, but my understanding is that they were simply living our their faith, amidst awful persecution, and that is what spread like wildfire.
Let God worry about showing the world how His children can impact culture. And relax for once.