Guess why - because the East Asian customers want thinness and lightness over power. I know because in Japan, when people saw my Mac (a 2013 MBP), first they were like "oh a Mac, can I try it?", but as soon as they held it, they were extremely surprised by its weight (compared to some 11" Toshiba notebook they preferred). It's understandable because in Japanese and Chinese cities, city people rarely drive but lug around their computers in bags, up and down stairs, standing for 1-2 hours in the crowded subway, etc.