Could one paint a masterpiece in poo? Maybe the good/bad taste (the poo) isn't the issue. Once it stops smelling so bad, and allowing for the fact the palette is undeniably limited. The question is how and by whom a masterpiece is recognized, diagnosed, decided upon, agreed upon and promoted as such. As with books.
On the one hand, I will not look at a Gericault painting of a severed head because I like it. I had to as a student because I was studying art history, and artists work within a context, and this was his; the French Revolution and the rise of Napoleon.
But the artist is saying, well, look here, we have this thing going on. A revolution, and we've set up guillotines. You know, if we think some folk have got more money than we approve of, like say, this little teenage girl here....rich daddy and mummy, off with her head. She gets to sneeze into the sack, serve her right for say, all the little girls of the poor, run over by the carriages of rich folk, and left for dead on the road
And you do a thing like this to someone, and you think it is fair enough on grounds of say, equality for all, when it's anger doing the job, and the quest of vengeance, and her right to keep her head is not equal to your desire to cut it off, well, OK but then you need to know the truth of it. What it looks like. Mme Roland dragged screaming to the guillotine. She would not die with dignity and make it easy on them. She was being publicly murdered, and had decided to behave as such, nothing to do with her courage or lack of it. And she had supported the revolution. Egged them on. At the start. But still not enough to save her once it got going.
There is art for beauty (and that's a matter of taste, but a still life painting still might well have a dead chicken in it ) There is art that tells a story, and some stories are not compatible with good taste. In fact, I'm not sure that any of the world's greatest stories are remotely compatible with good taste.
Jesus, nailed to a log and a cactus, sorry, crown of thorns, stuck on his head, and all of it happening in front of his mother. Shockingly bad taste, all those thousands of paintings. Here is Max Ernst's painting of him in trouble as a small boy.
Good taste? Bad taste? It's in the eye, or rather, the sensibilities of the beholder. What artist, apart from someone working to order on an (agreed) commission, could possibly legislate for all that, and still feel free to paint? Or in the case of writers, write?
It comes from inside of them, it's driven by the thing called the Muse, and then it may become timeless. If it is produced to please, safely, safely, taking not a risk, it's going to be a pale tame thing. Slight. Ephemeral. Or downright dross.