Well, thank you. I didn't realize I was deficient in my understanding of what "art" is. I'm married to an artist (watercolours, conté, charcoal, etc.), and in my immediate family is a writer, a poet, a singer, a musician, a folk-craft maker, and a craftsman specializing in metal. In my slightly wider circle of family and friends we have more musicians, photographers, potters (ceramics), and woodworkers.
As for your reference, it points out that art has fulfilled many functions over the span of history, including being an instrument of state propaganda, a method of enforcing conformity, a way of showing status, a form of rebellion and a form of self-expression. Prior to the invention of the printing press, "art" was an important method of disseminating information (along with songs and storytelling).
There is a correlation between the wealth of a society, and the degree that "art" is practiced by the population. Art, like any other human endeavor, evolves with the times and occupies new ground as it becomes available. It happens that "self-expression" (that you claim has little to do with art) IS one of the main drivers of the current understanding of what art is.
As for your last point (#2), is anyone seriously arguing this point in this thread?