I wonder if it's because Ishiguro - even though he's lived in the UK since he was five - feels that he's an outsider (as so many writers do, wherever they were born and end up living) that his themes are alienation, cloning, loneliness, the difficulty of making emotional connections? Or perhaps where he was born and where he lives have nothing to do with it. Still his themes remain.

Klara and the Sun's theme is human loneliness, set in a future in which emotional connections are difficult to make or understand, a place where children are either lifted or unlifted (states which are never truly explained but have to do with genetic augmentation), a place where lifting can cause physical illness and weakness. The reason that the lifted (or not) states are never truly explained and the emotional connections are fundamentally not (or mis-) understood is that the narrator is an AF (Artificial Friend): she can only understand humans though what she observes. And although she observes particularly well (according to her Manager) she has no hinterland of emotional experience from which to evaluate her observations. 

Which is perhaps why I, although fascinated by Klara and the way she worked in the human world (and what she observed) was left feeling just a little alienated by the story she narrates ... although I did feel compassion for her at the end when she failed entirely to understand what had happened to her, while Ishiguro skilfully conveys what happened to his readers.