In South Korea, 69 percent of adult smartphone users use a Samsung device, while only 23 percent use iPhones, a Gallup survey of 1,001 adults found. But the survey reveals a starkly different trend in one demographic: younger millennials and Gen Z. Among the younger generation, aged 18 to 29, iPhone’s share rises to 65 percent, double the Samsung's 32 percent, the survey found. This represents a 13 percent...