Aren't you a bit amazed that the WTS/JWS is still around ?
Nope! There are all kinds of ratbag religions that persist, sometimes for centuries. The Radio Church of God (aka, the Worldwide Church of God) my have continued as a minor example of Christian ratbaggery, but for the radical changes introduced by the 2nd generation leadership. If they had adopted a gradualist approach like our once dear brothers of the fourth generation leadership of witnesses, they may not have lost so many members.
And can you find a better example of persistence aalong with gradual change than the Roman Catholic and the Orthodox branches of Christianity