Over the ages, there have been lots of groups with different ideas on end-time prophecy and these groups eventually phase out of existence, even though they don't dissolve immediately when the prophecies fail (they get stronger at that point) but they don't stand the test of time. I assume the same will be true for JWs.
History repeats itself and in a few hundred years nobody on this planet will know what a JW was, but what is bad is there will be others to take their places.