Adopting/Contributing to the project as their number one mapping foundation would be nice and would have provided them tons of goodwill. But I guess Apple also wants to use OSM together with data from other commercial sources (tomtom).
That applies to the strange, pre–iOS 6 iPhoto-specific map tiles. OSM is acknowledged in the new app's acknowledgements, but so far there are places where the Maps.app is less detailed than the basic OSM database – but no doubt this can and will get better.
http://blog.osmfoundation.org/2012/03/08/welcome-apple/
Adopting/Contributing to the project as their number one mapping foundation would be nice and would have provided them tons of goodwill. But I guess Apple also wants to use OSM together with data from other commercial sources (tomtom).