What Makes a Market for a Start Up?

I've always been bothered by descriptions of the market as something that you map discover. To me, the best metaphor for getting a start up is like producing movie. Unlike a movie, which is incredibly expensive and difficult to refilm it's possible to fix calebrate the vision a bit to sell more tickets. So there is some feedback loop that's possible. But i don't think you're really correcting the mackro vision.