Part of the problem here for self-published authors is that they don't have the marketing dollars and platforms of traditionally published authors available to them. It's hard for me to work out when new releases by these authors are coming out at all if I don't subscribe to their Twitter feeds and even then I miss a lot if I'm not following religiously. Amazon isn't much help because it seems to be hit and miss whether they pick up that you bought a self-published author's first book when they make recommendations on what you might like to read next.
I suppose these are kinks in a newish system and readers who are devoted to particular self-published authors will make it a point to seek out their new works and know when they are repackaging old works. But it is definitely more work for the reader to follow a self-published author than a traditionally published author whose new book will appear on library shelves and on the bookstores' new release shelves more automatically. So this is yet one more challenge for self-published authors - and their fans - in the digital publishing era.