At bottom, I suspect that Nietzsche — a world class literary artist but really not much of a philosopher (arguably) — was simply recognizing the negative aspects of the Enlightenment (its atheism and materialism), and their impacts on human thinking and on human society at large. When he said, "God is dead! And we have killed him!", I'm not sure the statement necessarily has a triumphalist ring to it....
The point is not so much that "God is [literally] dead." The point is: He has "died in our hearts." Faith has died.
I think Nietzsche was, in the last analysis, a deeply tormented soul. He was an orphan raised by maiden aunts. There was no father figure, no male role model in his life. Eventually, he contracted the syphilis that killed him (after having reduced him to a raving lunatic), either at a Jena bathhouse, or as a consequence of his service as a medic in the Crimean War, depending on which expert you listen to.
Yet it seems clear that he was a harbinger of the Spirit of the Age, which Ms. Kimball so ably describes.
Just one nit-pick: Ms. Kimball should blame Descartes for the mind–body split. Descartes, a brilliant mathematical thinker and philosopher, was working out the implications of the great Newtonian mechanical system that had become the major paradigm of science by his day, as they apply to man. Kant got the idea from him.
Thank you for posting this wonderfully insightful and thought-provoking essay/post, dear spirited irish!
I agree with your assessment of what Nietzsche was saying, not so much that the deity God had passed on, but that God was dead for us and was no longer a driving force in our lives.
And I think, for most people, he was exactly right.