Publishing is becoming more and more easy for individuals to take on themselves, at least in terms of production. What can't be as easily replicated though, is the brand and distribution arm of major (and even smaller) publishing houses. Yet, the allure of self-sufficiency and control over one's work, combined with the ease of production, is attracting authors of all genres.
In the past, author David Maister went the traditional route, and is now trying his hand at self-publishing. Admittedly, he doesn't know how successful this will be for him, but he has hope that it will work. An important thing for other authors to consider, is that his book is building upon the attention he has received from his previously published (by publishers) books.
Similar to the recent Radiohead phenomenon of them offering their new record as a download for a "pay what you want" price, having a large, dedicated audience in tow gives you more leverage when taking your work entirely in-house. If you have such an audience, it might be something to consider. If not, you might be joining the masses of self-published authors who will begin to work more on the administration side of their book, than spreading the idea of the content.
Check out David Maister's reasoning behind his decision to self-pub at his blog. One disclaimer though, he mentions the ability to get your book on 800-CEO-READ's site even if you self-publish. While this is possible (it is in Maister's case), it is a rare situation and won't work in every scenario of self-published authors. Something to consider if you decide to take this route yourself.