Betty and Phil Scheiber enjoy quiet afternoon walks through the air-conditioned corridors of the nearby Oxford Valley Mall. After a year of mask mandates and social distancing, the retired couple from Middletown thought all malls were struggling like Oxford Valley, with two boxed-up and shuttered anchor department stores, two vacant food court restaurants, and 16 other smaller retail locations closed. Then, they took a trip to King of Prussia Mall in neighboring Montgomery County. “I was in awe,” Betty said. “My mouth nearly hit the floor.” She waited 40 minutes in a line that stretched around the Gucci store at King of Prussia. Phil got through four chapters of the latest David McCullough biography while sitting amid the orchids and metallic art installations outside the Louis Vuitton.