If I understand correctly, your belief is that the art of 'highest value' is created in a vacuum from the approval of others. That's okay. However, for myself, and usually for most others, the most valuable art is simply that which brings them the greatest joy.
When it comes to creating art, I receive the greatest joy when I'm also giving others joy. I'm much better able to give others joy when I consider their tastes. So I take my own (actually quite extreme) desire for experimentation, my own sense of aesthetics, and find where that overlaps with people's tastes. It's a hybridization. Not top-down, or bottom-up.
My argument is that most people, being essentially prosocial, gain the most fulfilment when they incorporate the tastes of others. And sometimes, our value system can make us feel less fulfilled. In this case, I believe that the value system of 'ignoring the approval of others' makes most people feel less fulfilled.
Simply put, it's like sex: the best sex is simultaneously self-focused and other-focused. I view art exactly the same.