I assume the parent comment's last paragraph is why every fantasy novel I've read in the last decade has a five-page-long lesbian romance; the author has to play ball with the publisher in order to get marketed.
I think all disciplines start “hard” and objective, getting into the subjective at a more advanced stage - at the very least it is easy for a knowledgeable reader to know when an author is actively choosing to disregard an established rule and when it is incapable of following it.
Saramago, the novelist, is famous for writing unconventionally, with long phrases and sparse punctuation, but nobody doubts he could have written conventionally. Same for Picasso rejecting realism.
Many famous authors right now would clearly have a hard time following the “base” rules, and that for me warrants judging them by hard rules. If they could, and got into the twisting rules phase, then I agree it becomes a far more subjective matter.
Media takes time to consume, which means that many products won’t be consumed at all even if they are good, much less be consumed enough to reach the point where word of mouth can achieve virality.
The reality is that the best winner is usually a product good enough to not be laughed at (though not usually best in class), with some characteristics that make it marketable, and with strong backing behind (money, connections or both).
One funny effect is that you end up with artists talking about viral topics like social justice and discrimination like it’s first hand experience, but a quick check will show they come from immensely privileged backgrounds.