You are thinking in terms of neural networks and given datasets. Though, what prevents a computer from experimenting and trying new things out? If you have a dataset from which a neural network can learn what people may or may not like, you may have one piece of the puzzle. The dataset may also be used to measure how close or far away it is from the already existing work. This may give us the opportunity to find pieces which are likable and yet unique in some sense.
Now, you may let it experiment with different methods to produce images/music or whatever. It might mix them and try different things. When it achieved a few things, it may even mix those techniques to create something more unique.
I don’t see a reason why consciousness or other not well defined things would be needed, as it has been suggested by others here.