Your analysis is all perfectly correct if you presuppose that "art" is purely epiphenomenal. But if you start from the perspective that "art" is something in and of itself, with its own set of values that economics only tangentially interacts with, then you would view the ways in which economics reduces art to "mere" exchange value as positively immoral, if that's the right word.

To adapt a Father John Misty line: Maybe art is just an economy based on resource scarcity but I fail to see what that's got to do with you and me.