I think you young whippersnappers need a history lesson on UI design at Apple.
See:
http://en.wikipedia.org/wiki/History_of_Mac_OS
Skeuomorphism has been an integral part of Mac OS since the beginning and it is part of the reason why people found it so easy to pickup and learn.
Did you notice how Microsoft copied the skeuomorphic isomorphic design of icons from Mac OS into Windows? Win 3.11 copied ideas from the early Mac OS and Windows 95 copied ideas from Mac OS 7.x This continued for some time into XP and Vista.
Skeuomorphism could be found throughout OS X from OSX 10.0 through 10.8.
Why do you think OS X is so easy to pickup? Why do you think new users have such a hard time with Metro? Why do you think so many regular people hate the ribbon interface? Why do you think people hate Office 2013? It is so damn flat.
I think the current designers at Apple that are pushing for flat and anti-skeuomorphism need to be fired before Apple begins another spiral of death we had before Jobs came back. Jobs is dead now, so they need to find a new visionary. Sorry but Tim Cook is no visionary. He is good at COO duties but a horrible CEO.
Apple has betrayed its DNA.