Apple has had trouble with Big Data, in the parlance, but iCloud is still running. They've made some pretty dumb mistakes with their online services over the years, but they still do happen to be syncing data (if even just push notifications) to something on the order of a hundred million devices.
Catching up to where Google Maps is today will take somewhere between 10 days and 400 years. I'll bet good money that they have this nailed within a 95% tolerance before next year's new hardware model.
This is apart from MapMaker, and their dev teams, and their software improvements.
For instance, if you look at directions in India now, they're awesome, since they tell you landmarks to look for on the way [pass by * on left], at the intersections, etc. http://goo.gl/maps/b8w15 for instance.
My guess is 95% will take 3-4 years - once they accept they have a problem.
Fixing map data is.
