One reservation: a residue of elitism in the notion that a key to the fun of reading genre stories is the knowledge that we could be reading something better. Betcha some genre fiction defenders would find that patronizing.
"And part of the pleasure we derive from them is the knowledge that we could be reading something better, something that, in the words of [Matthew] Arnold, reflects "the best that has been thought and said in this world. ... readers who seek out mystery novels are seeking to escape not from life but from literature, from the 'pluperfect tenses of the psychical novel.'"Looking at the quotes again I realize he's being sarcastic; patronizing the snobs, if anything.