Should You Self-Publish? (part 5)

So I've written a novel, the first part of a trilogy, that takes place in the Solar Echoes universe. I'm standing on the edge of decision, considering self-publishing but hoping for a publisher. I've been querying agents and some publishers that are open to direct submissions. So far, I have not had success. The more time I put into query letters and other submission requirements, the more I wonder if I should take the path of self-publishing, again. I'm holding off on self-publishing the novel, though, because I've already had years of experience with self-publishing and I'd like to see what a publisher could do differently than I can. Would a publisher increase my visibility and sales? Would a publisher connect me with more opportunities? Most likely, yes, so I am trying to land one. But, this process can take years, and one has to ask after going through the process for a while if it will ever result in anything. There is one last, important tip I'd like to give on this topic of self-publishing, though. Once you decide to self-publish your book, you can't go back—at least, not for that book. Publishers do not want to publish anything that has already been published before, especially something you've self-published. So, don't pursue the route of self-publishing unless you are absolutely convinced that traditional publishing is not going to work for you. That may be the case for me, but we'll see. Solar Echoes as a game addresses a very niche audience—the sci-fi role-playing crowd. Solar Echoes as a story, though, will hopefully attract a much bigger audience. A lot of us must really love space operas, because if we didn't, Star Wars and Guardians of the Galaxy wouldn't be such big hits. I'll keep you posted on how the process goes for my search, and let you know if I decide to give up on getting a publisher and instead decide to self-publish. From the many people I've talked with at conventions, though, a lot of people seem to be interested in a Solar Echoes novel—would you?