First, I want to repeat the obvious: as soon as you think of fiction as a commodity, that's when the writing and innovation will slow down. That's when you will get scared.
Thinking of this as I read and re-read the 20 fictions given to me by Joseph Young and Kathy Fish for the vsf blog. These are two writers who have no fear that they will run out of stories, so it's no big deal to donate content to my teaching experiment. A writer who loves writing won't run out of stories. Or how about this? Maybe we've only got one story, and we just keep telling it over and over. Either way, there's nothing to protect. That said, as I prepare agent queries for my novels, I feel that fear. Big time. I would love to be brave enough to look into alternative models, but I'm not ready yet.
Not sure how this is related, but last week as I counted the sixth dead fox on the way back from our cabin in WV to our house in VA, I remembered last Autumn when we got caught in a long line of traffic outside Middleburg. Leaf peepers moving like molasses through horse country, and even though no one was going more than 15 mph, some jackass managed to hit a deer right in front of a farm mansion or winery. A man in LL Bean "work" clothes and a tweed cap was standing over it, disgusted. Just as we drove by, he pulled out a handgun and shot the deer in the head. Everybody was a phony that day, and then for one second we weren't.