Example: Cormac McCarthy's The Road. Gritty genre (post apocalyptic, guy with son), but beautiful complex writing, great thematic stuff.
In general, most genre fiction (PI novels, modern fantasy) isn't like that at all, though I like the genre part. They seem to be written for like a middle-school level of education and don't really have anything deeper to say.
Many books that have the beautiful, complex writing part and are thematic aren't something I have any interest in reading. I don't care about a multi-generational family story about mundane things.
I'm older so have read older books things that would fit this category (Lord of the Rings, No Country for Old Men, Raymond Chandler stuff).
by PencilBoy99