Marketing is just common sense?

This is a remark I hear quite a lot throughout the course of a year. Whilst I do believe that some people in the industry might lack common sense, to suggest that marketing is merely common sense winds me up. It is often used by people who produce mind numbing work that does the bare minimum. If this is common sense marketing then I don't want to be anywhere near it thank you very much. So in the words of George Bernard Shaw:

“He's a man of great common sense and good taste, meaning thereby a man without originality or moral courage”