It's fascinating to see a book go from 1500 books sold to bestseller overnight merely because of the author name. Is it just because there are so many authors and books that it's hard to find good ones, so people just stick with what's been shown to be good? The power of familiarity?
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.