(specs+tune-ability+ecosystem politic+marketing)/Price
That's the rational part.
I was one of the first buyers of their iPod, got the first 2 models of iPhones. Then after 2-3 years my phone started to get extremely slow after a few updates. Then I learned that it was purely intentional from Apple, a concept called ''programmed obsolescence''. They got sued for that big time later and lost money, had to backtrack, but I won't forget. Now plenty brands do smartphones anyway.
That's the frustrated part.