DavidChristopher
You are correct that Jehovah will use a messanger just like the last time. Convincing people to take a different path is not so easy considering Jesus was unsuccessful and so is the bible. It is a feat of impossible magnitude to change the world operating systems by way of world leaders and yet it is childs play for the Messiah. So what does it take to get the world to accept the operating system that Jesus recommended instead of the opposite ? It takes a messenger from Jehovah who leads by example to perform miracles and prophecies and afterwards reveals that he is the Christ just as Jesus did. That way all can review the evidence that was left behind and question the witnesses who saw it happen but did not understand.
How long must mankind wait depends on how long it takes the Messiah to find followers. The Messiahs performance is a piece of cake, finding a believer is not.