Organizations who consider marketing to be an art form are decades behind in their thinking.
While art is a component, marketing is clearly an applied science which combines research, economics and mathematics; as well as social sciences like psychology, sociology, and cultural anthropology. Companies absolutely must base their strategic decisions on these elements.
When it comes to advertising, promotion and branding, once the proper positioning strategy and key messages have been finally honed, strong creative in necessary to cut through the clutter and develop mind share.
At that point, art and especially design become important components, but not before all the heavy lifting is complete regarding the scientific portions of this discipline.