The lesser culture is always drawn to the higher culture (or the perceived higher culture).
Christianity always creates the higher culture, and as long as Christians hold strong to their beliefs, that higher culture will remain strong.
Sin is the disease of the world and Christianity is the immune system. But what happens when a previously Christian society turns it back on its beliefs? The immune system becomes an autoimmune disease — which is worse than the original disease that society suffered from before Christianity came in.
Today in the west, progressive leftist ideology is seen as the new higher culture. It is nothing more than a counterfeit Babel though. Nobody 30 years ago was thinking that we needed things like gay marriage (as one example). But now, if you speak out against gay marriage you will be labeled a hateful homophobic knuckle-dragger who is stuck in the primitive wasteland known as “The Wrong Side of History” where there is weeping and gnashing of teeth.
If Christians want to shape the future of the western world and plant more churches, they will have to rise up to the difficult call of creating the higher culture once again. It’s harder now than before. To bring a higher culture into a pagan culture is easier than doing it in a post-Christian culture where the blessings and benefits of Christianity are still enjoyed by the very people who are ignorantly rejecting its foundations.