I agree with everything you said here except the part about about photography not being art because it isn't based on drawing. Why do you say that being based on drawing is a necessary prerequisite for something being art? It certainly isn't for sculpture, music, literature, and drama. I'm not saying that drawing is an unimportant skill in the visual arts, or that it isn't even the most fundamental skill, but I don't see how it is a defining quality without which something isn't art.
