The lack of features in Maps was due to Google's restrictions in their api. It specifically prohibits turn by turn applications using their api. We also have no idea nor will we ever know if and what terms Google wanted to license Google Maps.
I find it hard to believe that Google did not want iPhones to have turn-by-turn. In their minds, the more people use their services the better. And I never saw one piece of evidence of Google crippling a product on iOS so people buy Android.