Ok, this is an interesting twist to the story. See my comments elsewhere on why I don't think an App version of Google Maps would see the light of day (if it did that would definitely count as 'plan C' in my book).
Apple lost this particular battle ( mobile search ) the day Google bought Android. OSM is cool as we know, but it was not deployed until now, and the reaction is epic. Apple will fight the good fight like bing is doing in web search, but ultimately will be found wanting, just like bing. The only f-u play Apple has left is to spend billions of dollars making OSM on par with GoogleMaps, contributing that knowledge 'upstream,'watching specialized maps services eat google maps' ad lunch. I seriously doubt that would happen, but it's the only play left. "If I can't play then no one can..."
I had this idea recently of splitting the internet into two internets: one for Apple fans and one for Apple haters. Apart from getting rid of a lot of flamewars, Apple could rule supreme in the Apple internet, be the best search engine there and so on. If you never know that there are better options, you can be happy.
Fun times.