For nearly two decades, Marvel superhero pics have more often than not kicked off the summer box office, which begins the first weekend in May. This year, Avengers: Doomsday was supposed to continue that tradition but when it became clear the tentpole wouldn’t be ready in time, top Disney movie studio executives were in a quandary as they gathered in a conference room at the Team Disney building on the Burbank lot that is famously propped up by the seven dwarves. Who could be their new prop be? It was Disney movie boss Alan Bergman who came up with a novel idea : What if they turned conventional wisdom on its head and instead tapped 20 th Century’s dramedy The Devil Wears Prada 2 to open summer? After all, the first The Devil Wears Prada became a hero of early summer 2006 when daring to open opposite DC and Bryan Singer’s Superman Returns .…