The strong selling point of iOS is consistency and order across all concepts. To me Android is like a mutagenic factory sewage - anything is possible for better of worth.
1. Allow new users to guess at the functionality of apps before tapping them. This is important for first impressions (like trying out the phone at the store before buying it).
2. Allow current users to quickly and reliably navigate to the app they intend to use.
It seems to me that instead of arguing about skeuomorphism, there should just be some good old A/B testing for these two use cases. And whatever wins is best. Maybe Apple has done this, maybe not.
It clearly isn't now, as iOS 7 is hilariously inconsistent with itself even within a single screen.