PONTIAC, Mich. — Even the great and powerful Oz could not save the film studio that was supposed to save this town. The studio, a state-of-the-art facility fit for Hollywood blockbusters, had risen from the ruins of a General Motors complex here. It was the brainchild of a small group of investors with big plans: the studio would attract prestigious filmmakers, and the movie productions would create jobs and pump money into the local economy. A glamorous sheen would rub off on this down-on-its-luck town. But in Pontiac, happy endings do not usually come Hollywood-style. The tale behind the studio,...