See Apple's laptops for an answer to your last question. In a field of $400-1200 laptops, they're selling $2000 machines very successfully.
PCs have already been commoditized, Apple has maintained their premium by offering something that noone else can: smooth integration and experience due to everything designed end-to-end by one company (and OS X).
PCs have already been commoditized, Apple has maintained their premium by offering something that noone else can: smooth integration and experience due to everything designed end-to-end by one company (and OS X).