Lord of the Rings is an exception in the film world. Because it was based on a trilogy of novels that had achieved worldwide popularity for over sixty years, the studio saw fit to fund all three films to be made together. As far as I am aware, this has never been done before or since in the movie industry, but with good reason. Such a strategy is a large financial risk to everyone involved.

If films are not developed separately to capitalise on the previous films, then trilogies are developed using a two-step rule, such as with the Matrix and Pirates of the Caribbean. If the first stand-alone film sells, then two films are made together to capitalise and expand upon the original film's success.

If you can sell one stand-alone film script to Nintendo and make money at the box office, then they will feel confident about developing your trilogy. But they are going to have very little confidence in developing a full three films together that may turn out to be a major loss and damage the credibility of the franchise. It's too risky.

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Zelda Magic Article / Zelda Symbolism Article / The Announcement of the Split Timeline, and the hilarity that followed