“Antiques Roadshow,” a mainstay on PBS for the last 25 years, is known for its jaw-dropping appraisals of collector treasures. But it turns out that most of the time, owners aren’t actually selling their items. An estimated 90% of the items featured on the program aren’t sold after their appraisals. With such low stakes, why is “Antiques Roadshow” one of the public broadcaster’s biggest hits? Freelancer Stephen Lurie recently wrote about the show’s enduring power for The Atlantic.