Art is communication, just like talking or making a movie. Art is a way for an artist to send a message to the audience. When people say “I don’t understand the art”. That is the same as not getting the joke, though the joke is there.
Art becomes a business when the artist or someone who works with the artist deliberately produces the art in scale. That is step one. Once the art has been produced in scale, then the artist sells the art. After the art is sold, the profit is reinvested to create more new art or increase productivity. Once this cycle is formed and for as long as it continues, making art becomes a business.