When I first began to think of writing as a career, it was my unquestioned assumption that traditional publishing (ideally, being represented by an agent and negotiating a book deal with a major publisher) is the Holy Grail for any author, anytime, anywhere, myself included, and the only ones who self-publish are either desperate losers or people with a massive online following and amazing PR skills.
Fast forward a few years (and many dozens of rejection letters), and I'm a little wiser and a lot more sober. I've discovered many fantastic books and whole genres that don't fit little pigeonholes of traditional publishers; and I've had the privilege to meet successful indie authors who won't trade their creative freedom and high royalties for the carrot dangled in front of them by trad publishing.
I've also acquired a certain moderation to my views. Self-published authors are not the dregs of trad publishing; neither are they all a bunch of misunderstood creative geniuses trad publishing has missed out on. And yes, I am forced to admit that there are a lot more substandard indie books than trad-published books, because uploading to Amazon Kindle is free for all and nobody can tell nobody they can't upload and advertise their unedited Zombie Vampire Werewolf Epic Erotica (and a good thing, too). There are no gatekeepers with indie publishing (except the readers, who vote which books deserve to live and which are doomed to obscurity).
I have also, upon reflection, found myself in a position of choosing self-publishing as a preferred option for my upcoming Viking-era novel, The Greenlanders: A Tale of Sea and Steel. I self-published Quest of the Messenger because I was rejected by traditional publishing. But I'm going to self-publish The Greenlanders (unless one of the best agencies I have already queried gets back to me with an offer of representation - and, let's face it, the chances of that are slim) because I choose to, mainly for the following two reasons:
1. I want to be in control. This is a story which I've been dreaming, breathing and living for many years - long before I began actually writing it (which was six years ago). It is very important to me to tell it the way I envision it and the way I want it told.
2. I am targeting a specific audience. The Greenlanders is meant for Viking-era lovers, who are a pretty specifically-targeted bunch. This isn't to say that people with a broad interest in historical fiction or the Middle Ages can't read and enjoy the book, but the biggest tag of it is 'Viking'. This comes in contrast with my other fiction, which is targeted at much broader audience.
Does this mean I'm burning bridges with traditional publishing? On the contrary, I've signed a publishing contract for Wild Children (and its sequels) and I'm currently seeking literary representation for my MG fantasy novel. But I'm glad to live in an age when authors have more than one viable option.