The longer Google takes on releasing an app, the less of a mistake it will be. From many of the post I'm reading, people are getting used to the Apple maps and most in the US do not have major issues with the map app. The exception would be overseas (especially the UK) where there are lots of problems in the mapping database. Unless Goggle matches Apple's app on turn by turn and other features, I can't see everyone switching back to Google maps. Especially when Apple cleans up it's mapping database.
So what you're saying is that Apple's maps are only a disaster for a significant majority of it's userbase.