Much of the rejection was a conscious desire to escape Christianities sexual restrictions.
By 2016, Christianity for ordinary people was being openly mocked and derided. Instead of "godless" humanism, the ruling class was turning to neo-paganism, animal worship, Islam, and Wicca or Witchcraft. Throw in some Buddism and new age variation if you like.
Christianity is what held together Western Civilization. Cultural Christianity combined with Science = the scientific revolution, the industrial revolution, and the most prosperous, free, and powerful nation in the world, the USA.
Without Christianity, cultural Christianity falters and falls apart.
Having grown up in England during the ‘70s and ‘80s, I can tell you the general population had already walked away from Christianity.