Recent stats in a few of the more religious western countries show that religious belief is decreasing at a rate of around 1% per year. (Eg Pew report USA, Australian Census, and another recent survey in South Korea.) We live in a historic time where religion is losing its relevance at an astonishing rate.
It is not just Christianity that is dropping. I know of a Japanese family; grandmother a devout Buddhist with ancestor worship, etc, mother lights an incense stick once a year, kids have no interest in religion whatsoever. I know a Hindu family much the same.
I have recently noticed that, while some millennial Muslims are devout, a lot of millennial Muslims appear to be atheists. 3 times in the last couple of months, I was told something like "no, I was just born Muslim". About a week ago, a millennial Muslim named Mohammed (born and raised in a country bordering Israel, but went to Uni in a Western country) told me organised religion is just a tool to control and manipulate people. He said that in front of another "born Muslim" millennial. They still seem anti-Israel though, which I found interesting.