The real question is: How many Apple users or would-be Apple users consider mapping to be critically important?
This could be a very interesting case study on sales of an otherwise great product being hurt by a move that cripples a critically important element of said product.
I've already met several people with iPhone 4's (or older) who said they are not upgrading to either iOS6 or iPhone 5 because of the mapping issue. I am part of that group as well. I'll have to buy an iPhone 5 for development purposes but I don't think I'll have it as my primary phone until the whole maps business is sorted out.
Mapping seems to be one of those things that you can't design your way around. In other words, nobody cares about beautiful inaccurate maps. This could be one of the first challenges on Apples's desk that can't be solved with cute commercials and pretty design. It has to be good and at least equal to, if not better than, Google's offering.
Regrettably sometimes the only way to get good at something is to start doing it. At first you'll probably suck at it but, with time and effort, you'll get better and better. This is Apple getting on that path to excelling at mapping. It'll take time. There's no doubt that they have the financial resources to make it happen. Now it is about execution.