Probably an accurate statistic.
This got me thinking. Of those writing a fantasy or sci-fi novel (let's say it's really 1/3 of all readers in these genres) how many will actually produce a finished work? Of those that finish, how many will submit to publishers or agents? (Or even, how many will submit to a vanity press?) Of those that get submitted somewhere, how many are read by a decision maker (i.e. editor) at a traditional, reputable publishing house? How many actually get green-lighted for publication and eventually make it to your local/online bookseller?
I was perusing the F&SF aisles of my local B&N recently, and was impressed that there were a lot of F&SF writers out there, many of whom I'd never heard of before. I'd wager there are somewhere in the hundreds of writers actually producing publishable material.
So, I tried to extrapolate the number of active readers in the community (which is hard to do, sales figures are difficult to rely on). So... I'm thinking maybe there's something like between 1 Million and 30 Million readers of F&SF between the US and Europe. This suggests there might be between 300,000 and 10 Million budding F&SF novelists, we'll estimate the number at roughly a million of us. Now it'd be tough to generate an estimate of how many of us actually finish a work - there's no published stastitic we could use for such an estimate that I'm aware of. But we can see that somewhere along in the above process, there's a precipitous drop from the number who are trying to write a novel to those who actually make it to the bookstore shelves. We're looking at a stat that may positively be marginally better than one-in-a-million, and could easily be much, much worse. Them's long odds!
I don't know if this thought will motivate us budding writers-to-be or discourage us? Me, I guess I'll keep on writing, no matter what, because even if I can't make it, even if it's truly impossible, I still love the craft.
Now... if only whenever I tried to take a postive step toward writing, since I hit a time-consuming snag that could take months to unravel in creating my map, I didn't keep hitting a point and saying to myself: "How can I write about 'x' without a half-decent map?" If only I were satisifed with a rough-and-ugly sketch!