It may surprise people to hear this, but it is true. The production team and the executives supervising spend most of the time during which a movie is made sweating over the story and the acting; the special effects always come last. Given how many mediocre or outright bad movies are made every year, I'm sure it's hard to believe that. But seriously, the largest amount of time is spent trying to finesses dialogue and reshoot scenes that don't work. You'd think that with films heavy on FX that it would be reversed, but it really isn't. FX always come last in the process; plot and character always come first.
Of course, that inadvertently speaks volumes about how different executives and studios view issues of story and character all in wildly different ways.