TADASHI YANAI, FOUNDER OF THE GLOBAL clothing retailer Uniqlo, is on the other end of a videoconference screen. From his Tokyo office, Yanai-san speaks enthusiastically about Uniqlo's innovative fabrics. "Americans believe cotton is best," he says, "but we've invented new fabrics that will change your lifestyle." First, Yanai marvels over Heattech, a proprietary warmth-generating Uniqlo cloth developed in partnership with the Japanese company that provides carbon-fiber for Boeing 787 Dreamliners. Next, he boasts that Airism, Uniqlo's cooling fabric, is "so light you don't even know you're wearing it. It is the number-one...