After having this book sit on my currently reading shelf for a long time, I've finally decided that I don't like the art (though the book itself is good) and that I agree with Bacon's estimation of Hockney.
Perhaps the problem is simply that Hockney is a good artist in a shallow time. But the problem, of course, is not that... but, fundamentally, that he ACCEPTS his times. In times where history is real, the great artist has both to reflect his times and transcend his times. But in times when history holds us all in the grip of an illusion or a neurosis, the artist (perhaps?) needs rather to REJECT his times, even as he transcends his times.
Perhaps this is wrong, and Hockney is simply 'kitsch'.... But that, then, simply begs the question of what is 'kitsch', and brings us back (perhaps?) to my previous comment.