Re: In case you've been living in a shed in outer mongolia for the last few years
I have no idea of the exact circumstances preventing the iOS-version of Google Maps being upgraded properly (turn-by-turn, data caching being the most useful things), but it seems clear that the primary mapping application for iOS absolutely needs these features.
Either Apple weren't willing to pay Google enough, or Google weren't willing to cede a competitive advantage that Android has over iOS, or some combination, or an argument in a toilet. Who cares? It's irrelevant, iOS needs a primary mapping app with up to date features, and so Apple had little choice once / if negotiations broke down.
I'm no apologist, but the facts are that Apple have been investing in mapping technology and companies for years now (google search will throw up many results), and as a consumer I'm happy to see competition to established players.
But it is a V1, and not a very good one - they have a huge amount of catching up to do, and given the much more closed nature (Gmaps has become so good partly as a result of independent contributors), they may find this difficult. Perhaps they should have just coughed up...