My thanks to Stephen Boydstun (in post 12) for calling to my attention the book Inventing the Individual: The Origins of Western Liberalism by Larry Siedentop (2014)! I came across a similar book about 12 years ago which was lightly discussed on the WeTheLiving.com Atlantis forum. I haven't read either book, but the ideas inside certainly seem important, however profoundly mistaken.
I carefully read the first 4 of 27 sections, and 48 of 442 pages, of Inventing the Individual. It doesn't seem worthwhile. It's five main authorities are hopelessly obscure, and most of its initial claims are false, misleading, or irrelevant. It's also immensely boring -- which is often a clue to a book's quality.
Still, these are ideas worth considering! Ayn Rand herself seemed to fall victim to some of the above pro-Christian fatuous claims.