It shouldn't take that long for the majority of the country to be religiously unaffiliated. Almost certainly in our great, great, grandchildren's time. The percentage of disaffiliation in the Silent Generation (my parent's generation, I'm 53) was about 9%. It was 16% for the Boomers, over 20% for Generation X, and almost 30% for Millenials. The great grandchildren of the Silent Generation have triple their religious disaffiliation. That might not happen again, but double seems to be xomething reasonable to expect.
I'm not anti-Christian. I'm anti-stupid.