Games like Final Fantasy (
http://www.youtube.com/watch?v=naUSBEVRLng) have a very short time at the market. It is a very big risk to finance a project of that scale. Many fail, deerly, to the financier's demise too at times. And, besides, if the story is developed in public, where will the "surprises" be?!
However, Other, far less story-based games like Tetris and Quake, do have a market too. Did you know that the best selling games are not story driven? Or, they have a setting which doesn't need 20 minute explainings.
Call of Duty, the Modern Warfare series are the best selling games ever. And, many open source project are decently close to them, in pace and style, even if it could be better.
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