Apple moat is its installed ios base of over 1b. That base has enabled apple to generate well over $30b annual in services. That's over $30b recurring revenue, that's almost facebook annual revenue. Or more than annual revenue of amazon AWS. Apple just need to continue monetizing its installed base and have reliable recurrent revenue. The replacement circle of iphones will get longer but that's not where the growth is, its in services. For my money, I'd short Amazon before touching apple.