I think this certainly has something to do with it. Also consider the commitment both buying a novel and reading one is for most people--as you said, folks would rather just stick with what's familiar and what they know they're going to like. I think it depends from reader to reader, however--I really enjoy to try out new authors all the time as well as new genres. But on the other side of the coin, my sister (also an avid reader) has a few favorite authors that she sticks with, and doesn't deviate much. We both enjoy reading quite a bit but we just enjoy it in different ways. Kind of scary, though, for writers at least. J.K. Rowling, author of a series that captivated millions, was only able to sell a measly 1500 copies when her name wasn't on the book! Yikes. Tough out there for unknown authors, I suppose.