I could understand upgrading so frequently at the advent of mainstream smartphones, where two years of progress actually did represent a significant user experience improvement - but the intergenerational improvements for most people's day-to-day use have been marginal for quite some time now.

Once you've got web browsers and website-equivalent mobile apps performing well, software keyboards which keep up with your typing, high-definition video playback working without dropped frames, graphics processing sufficient to render whatever your game of choice is for the train journey to work, batteries which last a day of moderate to intense use, and screen resolutions so high that you can't differentiate the pixels even by pressing your eyeball to the glass - that covers most people's media consumption for the form factor, and there's not much else to offer after that.