People don't value art.
At least not how the code values art. The financial worth of artwork determined by the system represents a character's skill and stats. It's great to know where you're at and in an ideal system it'd mean great things for the artist and the buyer.
But it doesn't really for the artist a lot of times. Artists, like tailors, aren't suppose to make artwork for the express purpose of selling to the markets or some other little neat areas around the game. And that's a good practice, because it's a bit scummy to do with any consistency. Artists can try to put genuine efforts into finding someone to buy their art and if it doesn't happen I think they're allowed to go and sell through coded means, but that still feels scummy sometimes.
But that's a guidance/suggestion/rule that only applies to the artist. It doesn't apply to the people who buy the art for far less value than its coded worth. And it doesn't apply to people who take down artwork from public places or when they have the skill to uninstall it from private ones.
I could be upset at players who take down public art/vandalism art only to just immediately go and sell it to the markets. I won't lie, I'm a bit annoyed even now but when it boils down to it that's just taking advantage of how the system is. It's demoralizing to put time and effort into a whole little story and creating artwork and some RP only to see it up for a day or two and then once it's down you worry it's going to be right up in the market, and it often is, because no matter how much you @holdback it's still pretty profitable after a certain point.
It'd be different if that artwork stayed in hands and was exchanged between characters and even sold to other characters. But I don't think it often is. So that ends up with a very unique set of events where artists won't get paid by characters what the game says their work is codedly worth but the buyers or people to take it down can sell high end characters' artwork for more than any character might ever pay.