Organized religion is barnacle-like in its stickability. And just as barnacles don't use sweet reason to stick to things, organized religion doesn't either.
For example, the heyday of Christadelphians was several long decades ago, but there remains a solid core of loyalty to that millenialist movement which ensures their quaint little halls remain dotted throughout the land and reasonably well attended.
So, yes, JWs will be around for some time to come. But it looks pretty certain their growth heyday in the West is long over.
What will be open to screeds of speculation is the ultimate form their organization will take as the current decade passes - especially their ongoing reconfiguring of their central doctrine, the 1914 generation.
Jump forward to 2026: Don't expect a sudden lurch among (remaining active) members to 'reason' intelligently on the significance of 1914.
But do expect greater dropping off of zeal and a settling into a less urgent lifestyle.
Bring on the pinky rings and Apple watches!
Sums it up pretty well.