First of all, there should be no discussion that both Traditional Publishing and Self-Publishing have their advantages and disadvantages. So there is no 'us vs. them'.
Second, some established authors are putting their backlists up as self-published e-books. These books have been professionally edited when they were published before.
Third, some authors have slipped through the cracks of TP and are now exploring how to SP with e-books. Their writing is often quality and well-edited, but not deemed commercial enough for TP.
Fourth, there is a tremendous influx from amateurs flooding the e-book market with crap, trying to emulate Hocking and Konrath.
Fifth, there's a problem with distinguishing between the 'real books' and the 'crap'. Cream might float to the top, but so does shit...
I think what will happen is that word-of-mouth and independent reviewers will become more important. Sorting e-books can happen in different ways, but writers like Konrath stress the need for professional [looking] covers and good formatting. Also, writers need to be careful not to allow books hit the market that have typo/spelling/grammar issues. If possible, they should have multiple bèta-readers and perhaps freelance editors go over their manuscripts.
In the end, the better e-books will distinguish themselves in:
- sales numbers.
- multiple reviews, both on Amazon and by independent reviewers.
- media promotion on Facebook, Twitter, websites and blogs.
- excellent sample pages, that will draw the reader in and sell the book.
- reasonable prices.
If you read e-books, you will find a reviewer you can trust, just like the book review in your newspaper. Some books will become popular. While that doesn't equal quality writing, it's an indication that there's not much 'wrong' with them. They might not be to your taste, but that's where the free sample pages come in.
In fact, this selection process is not all that different from promotion by traditional publishers, except that the channels are more alternative at this moment - the e-book is slowly heading towards becoming mainstream, and will become a popular format in the future. Some people will buy books on the basis of advertisement, some because their friends told them, some because the price is right, some because they read the first page and it grabbed their attention, some because they read a favorable review on their favorite e-book review website.