One of the great things about the Kindle is that I can sample a chapter or two of any book in the catalogue. This is a massive benefit to me and I'm quite happy to shell out five bucks to buy something if the first couple of chapters hook me. Sometimes it works, sometimes it doesn't, but a free reading of the start of the book is an enormous benefit. It's a qualitatively different experience than hearing a track or a sample from a music service. So I'm not sure it really will help unknown authors become more widely read - it's free to try them already.
