I like to say that I was indie when indie wasn't cool. Back in the late 90's, I made a few half-hearted attempts to get published with one of the traditional publishing companies. But most of my books are shorter than what they wanted (mine average around 50k words, and most publishers want at least 70k, it seems), and anyway, I only submitted a grand total of three of my novels. All three were rejected with form letters.
The form letters really pissed me off. Not because of the rejection, but because of the impersonal nature of it. But I understood that the sheer volume of submissions made personal replies impractical. Basically those form rejection letters were the biggest indication that there was no point in even bothering with traditional publishers. If they had so many submissions that they couldn't take the time to give me an even slightly personal response, then I figured the odds against being traditionally published must be astronomical.
Actually, about the only encouragement I ever got was from Dean Wesley Smith. I submitted some short stories to Weird Tales and the Strange New Worlds anthology, both of which he was editor. He rejected everything, but did so with a few personalized, encouraging words. I always remember those rejections, even if he probably doesn't even remember me or my submissions, because I was glad someone had at least taken the time to give me a personal response.
See, it was never the rejection that bothered me. Someone could have told me my story completely sucked big hairy balls, and it wouldn't have bothered me. At least they would have taken the time to tell me my story sucked big hairy balls. That's better than a form letter that lists a whole host of possible reasons the story or novel might have been rejected, and lets you pick whichever reason you like.
Anyway, back to the question. I only submitted a few of my novels. The rest I published myself through iUniverse, way back in the late 90's and early 00's, when POD was in its infancy and iUniverse wasn't a part of AuthorHouse and was actually a reputable POD publisher. I never did actual vanity presses, because I knew they were a scam. But when iUniverse started out, they only charged a $99 setup fee, which included a cover designed from your own idea. The price seemed completely reasonable for a service that was the same as what Createspace and LightningSource offer today. So despite all the controversy around iUniverse today among indie authors, pre-AuthorHouse iUniverse was basically a Createspace clone (or rather, Createspace is basically a pre-AuthorHouse iUniverse clone), and I have fond memories of it.
I never liked the idea of one person at a publishing company, or a handful of people at publishing company, deciding whether my writing would ever reach an audience. What made these few people so freaking special that they had the power to withhold my writing from other people who might want to read it?
I set up a website in the late 90's where I ranted against the publishing establishment. This was in the days when it was considered shameful in most circles to be a self-publisher, and so my rants fell on deaf ears. But I was always proud of my independence, and these days, it annoys me a little that suddenly everyone is saying what I've been saying all along: down with the gatekeepers! But it's nice to see that the world has now finally come around to my viewpoint. I've ALWAYS been self-published, and proud of it, even when self-publishers (indies) were spat upon by both readers and other writers. I was fighting the good fight long before Joe Konrath ever came along.
But to answer the original question directly: what motivated me to become an indie author? My rebellious nature. The complete freedom to write whatever I feel like writing, without having to consult with some stupid editor at a big publishing house. Rebelliousness and creative freedom, that's what motivated me.
What are you working on next?
Multiple projects. I've got so many books I want to write, I have trouble deciding which to work on next. But right now I'm working on Zombie Galaxy 2, and Apocalyptus Interruptus. Those are two I'm actually in the process of writing. But I've got about half a dozen other ideas that are percolating at the back of my mind, which is part of my writing process.
In the grand tradition of the previous volume of this devastating series, further arguments against the validity of special relativity are presented. The shortcomings of general relativity are also addressed.