The abandonment of skeuomorphism was part rebellion and part caving to the ebbs and flows of popular design. When you move away from tactility and recognizability (familiarity), there is a greater burden on the user to interpret the intent of the designer. This is one of the reasons there has been a big surge in the use of animations in UI; because flat designs aren't as effective at communication as recognizable, tactile ones. Younger users of unique UIs and gestures have proven that you can adapt to new visual conventions and forms of interaction. The problem is that this is not Apple's ONLY audience. The Mac has always been attractive to people who want a more approachable, simple, user-friendly, less virus prone computer. This audience is typically less tech savvy and probably not a millennial. I further argue that the visual style of Steve Jobs was more in alignment with the innate desires of this archetype.