There's been a hype about foldable phones. While it's awesome to see screens that can actually fold, and there are softwares supporting this feature, I do not see foldable phones have much future. The key problem is now the phone has to be as twice as big, based on current implementations. Also, there is only one possible changes of the screen display size. This fundamentally limits the concept of a "soft" display.
I'm more believed in scrollable screens. See this year's scrollable TV at CES as a reference. It would benefit much more if the screens can be dragged out more and more. While you may still limit the scrollable length, and fix the scrolling distance for fixed screen size, we may no longer need an additional thickness of the phone. Like the design of Amazon's Oasis, or any scrolls, it would save so much space and the phone will be so much smaller in size.