To some extent, I am surprised Christianity in general, is still around. If humans were purely logical, there would have been a dramatic fall-off in belief, once the theory of evolution was widely known, and the discovery of DNA should have been the death-knell.
I think what happens is that the majority of people do not change their religious beliefs over their lifetime, and only a percentage of the next generation do. On another thread, SBF referred me to a book, where the author argued that the this generational drop-out percentage in the U.K. was about 50% since WW2.
Why have many of the more fundamentalist Christians (eg JWs) held on better than the mainstream religions? Probably because their devotees are more sheltered from outside influences, reducing the generational drop-out percentage. Where I grew up, the mainstream Protestants have gone from being dominant to virtually disappearing. The Catholics have held on for a few more decades (but it is clear they are going the same way). I think the reason for the difference is that Catholics have their own schools to shelter their kids from outside ideas, and it slows the process.
Similarly, I think it is impossible to shelter even Borg kids from the outside world in this day and age, and I think Watchtower and other fundamentalist groups will suffer the same generational drop-out, from now on. It is a shame it is such a slow process, and too late for many we know.