With self publishing now, it is likely that unpopular works will persist. Over time there is more of a chance that anything great that was passed over will eventually find it's audience. Whereas in the past that stuff that didn't get published may have only existed as a single or few copies and was eventually lost to the passage of time.
That would be great, but it assumes a writer with marketing and promotion skills. Even if a large potential audience exists for a book, reaching that audience can be very difficult, which is a big part of the value large publishers offer.
I am loathe to admit record labels providing any value, but they do this as well, helping good (and bad) artists rise above the noise floor to reach a mass audience.
