A different theory occurred to me over the weekend. To wit: that Android smartphones have grown enormously in order to accommodate LTE. Currently-available LTE chipsets are physically bigger (AnandTech made the case months ago that none of them would fit in the iPhone 4/4S case design), and because they’re so power-hungry, they require bigger batteries. Thicker phones aren’t going to fly. Thus: wider and taller phones with displays expanding to fill the surface.
Certainly makes sense. I've discussed Android smartphone screen size before, but this particular stance hadn't occurred to me.