I love my 2013 Moto X, with its 4.7" screen. One of the main reasons I haven't replaced it yet is I can't find anything on the market of a similar size, that will actually fit into the palm of my hand comfortably. I may end up falling back on a relative's secondhand iPhone 5 rather than buy a new phone, just because it's small.

I can understand why it's happening, though. Netbooks disrupted laptops while the smartphone entered as a new market. Tablets disrupted netbooks. Now smartphones are moving up-market, with phablets, and disrupting tablet sales. That's a large existing market for the taking, which will give much better revenue growth than trying to carve out a niche in the small smartphone segment.

I think we'll see smartphones continue growing into the 6-7" screensize range, so that they're sized for a purse or (barely) a large pocket. And then smartwatches will disrupt the low end, so that you don't need to take your phone out of your purse/pocket as often. It's already happening - many smartwatch models let you take calls & do anything voice-related on the watch, so you only use your phone as an input device when you need to type.