[ZeroGravitas]

No-one seems to mention the downside of this approach. The iPhone is going to jump from what has always been an okay resolution but is now becoming low resolution, to what is going to be a high resolution but not for very long because very similar phone resolutions have been available for about a year now. Newer devices will continually increase the resolutions available but Apple can't improve on theirs until they double height/width, and quadruple pixels again.

Similarly the iPad doesn't have steller resolution, and unless they want the dreaded fragmentation, they'll not be able to do anything about it until they can double/quadruple the screen from what it is now.

By locking themselves into these resolutions they wander far from the display screen sweet-spot either shipping cheap, low-res displays or expensive, high-res displays. They can't even go to triple current resolution, as that would still look grubby on the middle device without a separate image which defeats the point.

And, apart from certain types of apps, it doesn't buy them anything. When displaying video or images, no difference as it's just scale to fit regardless. When displaying text in books or websites, they take the quality hit whenever they're not at the top of the resolution cycle. In return they get app UIs that are basically hand-drawn pictures and grid-fitted pixel art.

It's an engineering trade-off, and for my particular uses, it doesn't really pay off.