I very recently discussed this with a friend which I always have design discussions with. It started off simple: why is Apple including all those wood-y and leather-y apps which either are a nice gimmick, or just fail to deliver. And who decides which apps will fall to the makeover?
Ice Cream Sandwich on the other hand looks like Google will get its OS-wide makeover Android has been needing; the question remains whether apps will follow suit nicely... but the styling of the new Android and its impending style-horrors when 3rd-parties will start restyling their own apps (I am looking at you HTC and SE) reminded me of how a geek will shop around and gather courage to style his own house.
The result (and I must admit I fall into this category often): 2 colours which contrast nicely, but that's about it. It lacks its own soul, is a bit cold and a lot of charm is often clearly lent from other sources. To make matters worse: where the style does not fit, it gets completely thrown out and it looks rather wishy-washy. It is functional though.
Apple on the other hand reminds me of an over-eager interior designer more often than not. He has all this different rooms and he has his favourite one! All rooms look similarly with a nice style. But the favourite room (iTunes) gets makeover after makeover while the rest remains in the old state. Sometimes the new style is so fun a few adjacent rooms get the same treatment. It takes a while before the entire house gets the same love and attention.
Meanwhile he has got a summer house (iOS) and he put a lot of love and attention in it. During the summer he polishes stuff and discovers his favourite rooms in the new house. In the autumn he returns to his main house with fresh ideas, gives the entire thing a new coat of paint; and so the story continues and continues.
With HP putting Palm down, we lost a bit of middle ground between the two and with Microsoft coming in with WP7 we are getting a fresh look at mobile computing. I think we will survive :P