Oh come on. I like to make fun of Apple maps as much as the next guy but the reality is that they aren't that bad. Certainly a few more iterations and constant development effort will iron out any quirks.
First impressions are killer. Even if they're improving, there is a harsh stigma against Apple Maps now, much like Bing, because it didn't meet user's expectations. So users are being comforted by a familiar and useful tool, Google Maps, which many people can use on their computers (Why is Apple Maps not bundled into OSX? Error reporting could be done much more efficiently and abundantly).
At this point, many people will ditch Apple Maps for Google Maps. And because of this, they will suffer from having less crowdsourced error reporting.
By the time it's as reliable overall as Google Maps, they will need to have a clear advantage for users to switch back. Deep integration with iOS maps might be the key, but lots of apps will now be integrating with the Google SDK because of user preference. Tricky situation.
I think you are vastly over estimating the number of iOS users who will seek to replace a default app. I'd wager that the friction of not being one of the default apps will ensure that Apple Maps continues to be the dominant iOS mapping app for the foreseeable future.
There are a huge number of un-tech savvy users with iPhones that barely download any 3rd party apps at all. Those of us who have been voicing our opinion about Apple Maps and anticipating Google's new app are the vocal minority.
That's a good point, but "Apple maps being bad" is not only experienced by users, but it's also a meme that's swept through the media as well.
Don't forget how valuable it is to be at the top of the "free apps" section in the app store, too. If/when people discover the app, they might like it more than the default app.
