Writing Worry #5: Lots of ideas, few finished manuscripts

Many people suggest that authors keep a notebook on them at all times to write down ideas and observations as they occur to them. The reasons for this written thought process is probably because ideas are fleeting and that they numerous.
Just about anything can spark a writing idea in my brain. It might be a news story on the radio. Maybe it's something my co-worker said in a passing conversations. Sometimes it's as simple as imaging living in the shoes of someone I see. The point is ideas are everywhere. I know authors often talk about writer's block and it might seem like a lack of ideas. When it happens to me, writer's block is more about not having the confidence to try something that might not work.
Great you say. With all those numerous ideas, I must have numerous stories to write. I do. The problem is that the road from idea to completed manuscript is a long one. An idea must be fleshed out and filled in. Usually I spend several days, weeks or years, daydreaming about an idea. It gets molded and shaped. It gets made into one story then torn apart to make another story. There's a lot of thinking and sometimes even planning that has to happen before an idea is ready to be made into a story.
Most ideas are just fragments. A character. A setting quirk. A plot twist. Sometimes that's enough to spark writing. Most of the time the ideas get pushed to the back of my mind or, if I am lucky, onto a random piece of paper. Eventually the idea will bug me enough that I have to start writing.
I'm somewhere between a discovery writer (pantser) and an outliner (plotter). I've actually got two novels fully outlined. Only one is at the top of my must write list. Most of my writing involves a spurt of typing until I can no longer see where the story is going or I realize I am missing something about the back story. Then I turn to outlining. I pick up a stack of paper and a pen. Most of my best outlining happens when I am supposed to concentrating on something else, such as at a meeting, presentation or a busy cafe. I outline until I feel I have enough to take me through the next section of the story.
OK, now I'm on a roll and typing. The grueling slog of writing and outlining continues until the story is done (hopefully). I've gotten sidetracked by competing ideas and waylaid by the real world. To date, I've complete first drafts of around 8 novels (from 50-100K words), 2 novella (20-40K words), and a handful of short stories and flashers. However, the first draft is really only the beginning.
On to the next stage, re-writing. I'm currently re-writing one of my novellas to incorporate a second point of view. It may actually bump the word count up to the novel range. I finished the first draft last fall and have been working on the re-writing since. It's a slow process.
When I'm confident that my story is worth sharing, I have to find beta readers. They are invaluable in finding fatal character and plot flaws. Writing groups, including online critique groups, can help with this. Of course, any criticisms must be taken with a grain of salt. I decided to re-write Spar after a reader pointed out several times how one-sided the story was.
Re-write. Edit. Repeat.
Finally, a finished manuscript. I've only been in this position four times (two novels and two short story). Of these, one novel and two short stories were published. Dark Heritage has yet to find a home, but some suggestions by a beta reader has given me inspiration about how to re-write it. Hopefully that will lead to a sale.
Ideas = uncountable
Sold manuscripts = 3
Unfortunately, I am not a person who can work on multiple stories at the same time. It tends to fracture my attention. So while I re-write Spar, my brain tumbles over the re-write possibilities for Dark Heritage and I try to resist the ideas that keep nagging me to be written.
There's the Alpha/Omega homosexual paranormal romance, the polyangry werewolf romantic erotica, the alternate history steampunk romantic adventure...
Ideas are plenty, but it takes discipline, creativity, skill and a lot of hard work to bring even the most brilliant ideas into fruition. And don't most ideas seem brilliant at the time?