Here’s the short answer: control.
I tend to obsess over my stories. I’ve spent months, maybe years, preoccupied with every finite detail and nuance, sensory detail and room set-up, plot point and motivation, hair color and presentation, etcetera. I map out characters’ bedrooms, how my characters walk, outfits, family histories, and so much else. However, as I understand it, a traditional publisher could dictate changes to my books. They could request I change a character’s gender, for example, or maybe key plot points. I cannot see a traditional publisher allowing some of the creative decisions I’ve made. For example, I created the narrator’s voice in Into the Unknown from an ungendered base. The character does admittedly lean a bit feminine (that happens sometimes), but I never officially assigned them a gender. I want the reader to decide how they perceive this character, which is an important decision for me. I doubt traditional publishing would allow them to be as they are right now.
Also, I get to set my own deadlines. If a lot happens in my personal life, I can push a publishing date back a bit without that much issue. I am already extremely productive (seriously, I have to remind myself to eat meals and take breaks), so convincing myself to do the work is not an issue. Occasionally, I might procrastinate something marketing related by working on something else, but I will get it done. In the world of traditional publishing, it takes a lot longer to get books actually published and someone else gets to set those deadlines.
I would also be expected to do a significant portion of the marketing work on my own anyway. I’m still not that great at marketing, and have a lot to learn in that area, but I get to move at my own pace as a self-published author. Some of the marketing I expect traditional publishing would do, or expect me to do, would likely leave a bad taste in my mouth. For example, Into the Unknown includes a deaf character as one of the mains. I refuse to use this aspect of this character as a buzzword or a lure to pull in readers. If a review does it, that’s the reviewer’s decision. But I refuse to exploit that character trait for the sake of marketing.
I’ve never gone through traditional publishing, so I may be wrong in some of these points. But, as I understand it, self-publishing is the better route for me.
Update: I’m surprised this post is this old. Since 2015, I have been more involved with the traditional publishing world. I actually apply somewhat-regularly for anthologies. Several of these entries have been accepted, and I’ve had an odd array of experiences. Most professional anthologies use editors that don’t always agree with me. I can accept criticism, but there’s a reason I like controlling my work.
For example, not all publishers allow authors to use they/them pronouns in author bios. I have a pronoun-free author bio I’ll use when publishers outright refuse to include my correct pronouns. I pretend this isn’t erasure so that at least my story can be included.
And I always feel like I break a little when I admit that.
It should also be noted that editors in the traditional publishing world still tend to fight me on the inclusion of LGBT characters. I can only think of one editor who was actually okay with me including queer characters, but she was editing a trans charity anthology. I’ve heard from other writers that things are getting better. I have, admittedly, seen more openly queer writers, but I wonder if that’s because I’m more aware of them. I haven’t seen an improvement in my personal experiences in the traditional publishing world.
Note from the future: I have since moved from public deadlines to pendings. This better reflects (in my experience) the unpredictability of the self-publishing world. I still maintain my own deadlines, but you’ll no longer see them on my site (at least for the time being). I know my own work habits well, and I can still decently predict how long it will take me to accomplish something. What I can’t predict? Other people and the things I cannot always control in my personal life. Want an easy example? I’m typing this during the COVID-19 lockdown.