Apple unveiled the iPhone Duo, a $1,999 foldable smartphone with a 7.6-inch display, which Bloomberg Strategist Mark Gurman believes could mainstream the foldable category. The device combines phone portability with a larger screen for gaming, video, and multitasking, launching October 23 after preorders begin October 16. Gurman expects adoption to widen over the next decade as costs decline and Apple expands leasing options.