Wearables could become the next big growth market for mobile devices, but they'll have to get more useful and less expensive first. That's how things look to Linley Gwennap, principal analyst at The Linley Group, which is hosting a conference on mobile processors this week in Silicon Valley. Smartphones and tablets have stopped feeding the kind of chip growth they used to, and new devices like fitness trackers and smartwatches aren't soaring yet, he said.