• Apple Watch: “The job of the watch is to do more and more things on your wrist so that you don’t need to pick up your phone as often.” 
• iPhone: “The job of the phone is to do more and more things such that maybe you don’t need your iPad, and it should be always trying and striving to do that.”
• iPad: “The job of the iPad should be to be so powerful and capable that you never need a notebook. Like, Why do I need a notebook? I can add a keyboard! I can do all these things!”
• MacBook: “The job of the notebook is to make it so you never need a desktop, right? It’s been doing this for a decade. So that leaves the poor desktop at the end of the line, What’s its job?…”
• iMac: “It’s job is to challenge what we think a computer can do and do things that no computer has ever done before, be more and more powerful and capable so that we need a desktop because of its capabilities. Because if all it’s doing is competing with the notebook and being thinner and lighter, then it doesn’t need to be.”

Takeaway number 2 regarding iPhone differentiation is perfect. Just a fantastic piece.