Apple implements an interesting layered user experience in both iOS and OS X. They've always done this to some degree; early on with Mac OS X, UNIX gurus could live comfortably in Terminal while those raised on the GUI of classic Mac and Windows would feel right at home in Aqua.
With iOS 4, Apple's mobile platform added similar layers of user experience. While an expert user could double click home to open up the Fast App Switcher, or hide multiple apps into a single Folder, casual users could keep using the iPhone or iPad perfectly well without ever exposing either of those UI elements. iOS 5 adds Notification Center to the mix. Experts can click and pull and expose greater pro-level features while someone coming from a feature phone can use iPhone as little more than a phone that plays music and takes pictures. And both can be perfectly happy.
OS X Lion even adds an iOS-like upper layer with LaunchPad, so now the UNIX geek in Terminal and the GUI user in Aqua can finally give their parents, kids, and non-computer savvy family and friends an iPad-like app launcher to use, compete with auto-save, restore, and a host of other, far more humane features.
Making computers more and more mainstream is something Apple's done from Apple II, through Mac, to iPad, and it's something they're continuing to invest in for Lion, and iOS 5. And their market share seems to indicate it's paying off.