I think this Steve Jobs quote sums up their philosophy pretty well: "People think focus means saying yes to the thing you've got to focus on. But that's not what it means at all. It means saying no to the hundred other good ideas that there are. You have to pick carefully. I'm actually as proud of the things we haven't done as the things I have done. Innovation is saying no to 1,000 things." (Apple Worldwide Developers' Conference, 1997)
Unfortunately, I think it was a mistake saying "no" to the ram upgrade. But Apple has always thrived on incremental upgrades. They have this knack of putting just enough new features in new products to keep people coming back, but almost never anything more. The only iPhone update I can think of that wasn't very incremental was the iPhone 4.