OK, God is omnipotent, correct? God is love, correct? Why wouldn't he, for the sake of efficiency and accuracy, just make a general audible announcement that he's going to end the world soon and anyone who doesn't shape up is going to get the ultimate ass whipping?
Why would he want to use lazy assed JW's, who are more interested in counting their time than saving people, to do such an important work.
Because, the whole notion of preaching the end of the world is folly. It makes no sense. The world will end when either our sun burns itself out, or a giant meteor hits the earth or one of the other planets in our solar system and pushes it out of it's orbit.