Yes, there can be varying levels of diversion from the reality that we see around us. However, a world where magic exists, or a story set on a star cruiser, can contain as much 'real' about the human condition, as a novel set in 19th century China or Russia, both of which convey a 'real' world setting that will exist for the average current US reader only in the author's ability to evoke it in the reader's imagination, and having rather less in common with their views of reality than we'd like to admit.

Reading fiction is to partake in another person's imagination with our own, to allow their words to create something that doesn't exist. Even if the author evokes hardline reality, fiction is still a fabrication. It is a fabrication that we can relate to, or glean perspective or further understanding from, that we can sometimes relate to in various ways, but it is still the made up stories of one person being read by another.

Reading isn't science. It isn't math. Reading is of the mind, the heart, the imagination, the emotions. Defining what is real in those terms can be a difficult task.