"How big does one's audience have to be to complete the reader/writer relationship? Is one impassioned reader enough?" Yes, if your goal is to reach out and communicate. No, if your goal is to earn any money from your work. "And how does one prevent the publishing/marketing experience from 'chewing up' the author?" Being respectful, realistic, compassionate, and professional. "It does make me wonder if the business of publishing corrupts the writing process enough, that possibly fiction writing at least is better thought of as a hobby than a livelihood?" The folks who make a living writing novels would probably challenge that question! The business of publishing and the process of writing are not necessarily incompatible. The dreaded editing, revision, and marketing sides of putting one's work out there are often stimulating learning experiences, not always traumatic. In fact, some writers find the writing hard and the rest of the process easy. It all depends on one's personality, the type of work one does, and the environment one has to deal with.