I think it's important to note that it's not just the WTBS that is in trouble but organized religion across the board. Attendance is, belief is down, there is infighting in the RC church on a massive scale at the very top of the heirarchy.
When you think about it the hard science era has not been around for very long, giving people rational explanations for the world around them. Religion has been losing ground consistently since we've moved into the modern era and that makes complete sense.
I think the WTBS goes the same way mainstream religions will go over the next 10 years, more and more towards the margin, only a little faster given their end times theology falling apart and not having the deep bench of the mainline faiths.
I could see them being down to half of today's numbers or even less in 10 years and so inconsequential in the big picture as to fall out of the masses' consciousness. Oh yes, those folks, are they still around?