Thank you for this, it seems like a pretty thorough rendition of the history, at least as far as I know it. The one small addition I might add is a bit of pre-history to the Progressivism side of things. I think that the argument that "Progressivism" is basically the lineal descendant of Unitarianism, which grew out of a more-or-less merger of Puritanism and Quakerism, which were themselves prominent versions of protestantism is pretty well-supported, and one that I've seen some rather different thinkers come to (Mencius Moldbug/Curtis Yarvin here: https://www.unqualified-reservations.org/2007/07/universalism-postwar-progressivism-as/, Scott Alexander here: https://slatestarcodex.com/2016/04/27/book-review-albions-seed/, JMG, in, I believe, After Progress. Jordan Peterson might make the same point somewhere, but I can't remember well enough to track it down).

I also wonder if "Progressivism"/the religion of progress might just be the Faustian mindset taken to extremes, but then, I'm smack in the middle of The Decline of the West, and so Spengler's thinking is exerting quite the influence on mine just now. Certainly the idea of infinite "progress" is very Faustian, but I'd have to think about it a little harder to decide whether the specific package of beliefs that modern progressives claim is especially Faustian (if nothing else, the idea that any one set of beliefs/behaviors ought to apply to everyone, everywhere, and the use of those beliefs/behaviors to secure power over others is pretty darn Faustian).

Anyhow, thanks much for the thought-provoking post.