A faltering economy, intense online competition, and a need to one-up their bricks-and-mortar rivals led retailers one after another to begin opening their doors on Thanksgiving Day, pushing the Christmas shopping season to ever-earlier starts. But employees forced to work the holiday rather than spend time with their families launched a vocal campaign against the trend, and now the pendulum has swung back the other way: Retailers are falling over themselves to announce they’ll be remaining closed this Thanksgiving Day.