Well, I don't know about that, but the icons have two purposes:
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.
