I'm not sure this adds anything new, but as an analogy consider this:
I've started businesses before. I'm quite comfortable with producing an ebook. I can, and would, figure out editing, formatting, covers, pricing, marketing, publishing, customer service and more. What I can't do myself, I could easily hire out.
So, why don't I just write a book and sell it
. Right, that would be your reaction to everything I wrote.
Some people are quite comfortable writing but would rather have a publisher AND an agent so that all they have to do is write and cash checks (probably small checks, but that's their choice).
The change that I do expect is increased competition will drive down the cost of these services. For, example I wouldn't be surprised to see super-agents who will self-publish for you. They would handle all the details, including promotion, for a percent of the revenue.