Having a steady supply of contract work kind of sapped my motivation to continue doing any writing on spec; the appeal of toiling away privately on a novel with the hopes that it will one day get published becomes a lot less attractive when you have offers from people who are willing to pay you to write right now. Once the contract work started, I also sort of rationalized procrastinating on sending out query letters for my unsold novel with the reasoning that my query letters would be a lot more impressive when I could start them with a paragraph listing the visual novels I'd worked on as a contractor, along with information about the number of copies they'd sold.
That being said, although I never sold that novel, the time I spent working on it certainly wasn't wasted -- most of my early gigs in the visual novel space came as a direct result of the strength of my portfolio, which included parts of the original manuscript. So, while I didn't sell the manuscript, it did help with the first few critical steps of my writing career.
In an interesting quirk of fate, the editor that I'm working with for one of my current visual novel projects is also a senior editor at Tor, so despite never sending out those query letters, I somehow managed to stumble my way into a working relationship with someone at the publisher. Perhaps the moral of this story is that all roads lead to Tor. :)