It does not matter whether a writer writes about any recognisable social or political subject as long as the quality of writing exceeds any such expectations.

Honestly have to agree with this statement, if we look at John Cheever’s writing we can see that it is the quality of the writing, and the depth of his characters, that make his stories readable as opposed to any sublimely social or political commentary, though these do exist too of course. However it is fundamentally the principle of a writer to help us escape existence and/or endure it by seeing the world in a new light, and by viewing things previously unknown or where one has held an opposite view, in a different way.  A political or social subject should always be secondary to the quality of the writing, and in the absence of any political or social subject the quality of the writing, if good, will still make a book enjoyable just on its own merit. I think there has been too much emphasis of late on deeper meanings behind books, trying to cram as many references as possible or cover as many social and political issues as possible, whilst neglecting to primarily entertain a reader through beauty of language, deep characters that a reader can get really attached to etc.