While this sounds like a cogent explanation...I don't buy it. The iPhone environment is as much three dimensional as OS X. Look no further than the frosted glass effects in iOS which are now being introduced into OS X.Fingers vs. Cursors
A Mac can give a 3D illusion and your little arrow just flies around in that virtual space. It starts to feel real.
A tablet or phone, however, is constantly pushing back...brutally reminding your finger that you're tap-tap-tapping on something hard and flat. Touch-screen 3D illusions remain just that: an illusion. And it's an illusion that your fingers are constantly confirming as false. Better to make things look flatter so that it feels like the icons are on the glass. The illusion of a "living magazine" is the better goal there.
In both cases icons are representations of apps and there's no tactile feedback to separate one from the other. A tap on my touchpad is no different than the tap on my iPhone or iPad.
To me it looks like two different teams designed icons for their respective operating systems. And please don't get me wrong. I don't hate iOS. I use it on all my iOS devices. I just think that OS X icons look much prettier than their iOS counterparts.
Well, it's Jony's second year with Photoshop, he got better.
This I could almost buy