-snip- “John Carter,” a big-budget science fiction epic from Walt Disney Studios that opened Friday and flopped over the weekend. Disney spent lavishly (some say foolishly) on the movie in large part to keep one of its most important creative talents happy: Andrew Stanton, the Pixar-based director of “Finding Nemo” and “Wall-E.” “John Carter,” which cost an estimated $350 million to make and market, and was directed by Mr. Stanton, took in about $30.6 million at the North American box office, according to Rentrak, which compiles box-office data. That result is so poor, even when factoring in about $71 million...