Apple's regression test pack for an iOS device must be humungous! The permutations of actions for testing are tremendous. At that's not even including SDK/API testing for Aps. I think people just don't really get that. It's not just about testing 'new features'.Software development at this level is not easy. The code is gigantic and 100's of people working on it.
I work in a small software environment where software is designed per device and there are still bugs. The only way to find bugs is through testing in most cases .