In a blog at the Harvard Business Review, entrepreneur Anthony Tijan writes that sometimes ignorance is bliss when starting a new business. He says, "Being unencumbered by external opinions allows two critical entrepreneurial traits to thrive: creativity and conviction."
Basically his contention is that if you don't know what can't be done, sometimes you do it.
I think the same applies to writing (which generally is an entrepreneurial activity anyway). Of course it does help to have mastered your craft, but sometimes it's good not to know too much about the marketplace. Perhaps she's overused as an example, but certainly it was a good thing that J. K. Rowling didn't "know" that a book set in a boarding school wouldn't appeal to non-British readers or that wizards are rather old-hat in this age of computer games. It's that "ignorance" that's made her the riches writer in the world.
What don't you know? Keep it that way long enough to pursue your vision. Maybe what you don't know today can help you tomorrow.
(One thing you do know is that you don't want anybody ripping off your material. Get tips on how to protect it, as well as information about my "Stop the Rip-Offs!" report, HERE.)