3d fly-overs are cool but.....how are you gonna see inside of tunnels, buildings, caves, trails lined with trees etc using planes?
You gotta get someone with equipment to physically go and capture all that stuff. Like what google are doing with the street view backpack.
Maps is no longer about roads. Its about cataloging the entire surface of the earth. I have no doubt apple will at some point make a competing product.
EDIT: However, if Apple decides to waive their rule about competing apps on the marketplace and allow google maps, iOS WILL have access to street view anyway.
I'd prefer to be able to see full cities and one day maybe large areas of the planet in 3D than see the inside a cave or a tunnel....