If Google would have bothered to keep the iOS version even close to what they offered in Android
Google never wrote the old Maps app for iOS. Google supplied map data and Apple wrote the app; that was the arrangement from the beginning. Ditto for the Youtube app: Google never even saw the source code for it, much less wrote any of it.
You're both right, according to the best public information available... Apple wrote the app, but was only licensed to use the raster data and forbidden from doing turn-by-turn directions or other modern features by the license. Google refused to renew the license without adding all kinds of tracking into iOS, which Apple refused to allow. Since the license was set to expire before the next major version of iOS would have come out, Apple was forced to switch maps in this version.
And it mostly succeeded. It's hard to argue that the new map imagery isn't way, way better than what Google previously licensed Apple. Map imagery is crisper, faster, caches better, and is generally more readable. And routing directions are actually pretty good, taking into account traffic, etc. It's really just the geo-location that Apple dropped the ball on, and the public transit that Apple needlessly complicated.
Geo-location is quickly being fixed, but is the biggest glaring problem and really the crux of the matter. Public transit has a million other alternatives in most metropolitan areas and does link directly from Maps, but is less convenient... hopefully Apple will revamp this in iOS 7 and allow integrated plugins for Maps.
In the meantime, it's nice to see Google bringing an alternative to the platform, for anyone willing to trade their privacy for better geolocation.