Maybe glassblowers, film editors, and sky-writers qualify, too. The word artist has so many meanings, after all. I think the defining attributes of art have little to do with its medium. Art has always been about process rather than product, and it seems to me that the very basis of art centers on an act of faith by the artist. Art always begins as a labor of love.
Art is about collaboration with reality.
It makes the unseen seen. It cannot lie. It cannot answer questions. It can only inspire thought. These intangibles are the fluffy stuffing of art.