Once upon a time, I had a really sweet client who knew I was a writer and would occasionally ask how my writing was going. I didn’t really think he grasped what it meant to be a writer (because I am a snob), so I would always answer in some short, generic way that discouraged him from asking too many questions. I’d say, “Oh, it’s going OK. I’m doing a little freelance work here and there, but nothing very interesting.” Once, I told him I was working on a book and he told me he always wanted to write a book.
“Why don’t you?” I asked.
“I know it’s crazy, but I’m afraid I would get a deal where I have to write like two or three books, and I’d get writer’s block for the second book.”
I actually laughed (again, because I’m kindof a jerk). That would be a lovely problem to have, but his real problem was that he talked himself out of starting.
Just start, guys. You don’t know where it’s going to lead. You might not even finish the project, much less get a contract and earn money for it. Publishers aren’t exactly handing out multi-book contracts like candy these days. The world will not know to miss your creativity if you never try.
If your fear is that you won’t be able to finish the project, try and set that aside long enough to start. You will start many many projects in your lifetime, and not all of them will get finished. You may find that the project isn’t what you thought it would be. You might put it aside after only a couple hours of work. But the sooner you start, the sooner you can find out and, if necessary, move on to the next one.