"But for the time being, there is no "gate-keeping" on the Net. Thus chances for a good book to rise to the surface and become visible are wholly dependent on luck."
I agree that a little more gate-keeping would be helpful, but I don't think self-published authors are wholly dependent on luck to rise to the surface. Self-published authors who tirelessly look for ways to promote their books can help make their own luck.
For example, a debut self-published author might comment on an article about the future of publishing and invite folks to check out the hot new time-travel thriller "The Dinosaur Four," which has a 4.6/5 star average (104 reviews). :)http://www.amazon.com/dp/B00KK1SU9W