The purpose of the "witness" work is specifically to generate a "new" nation for god to work with. This new nation, made out of people of all nations, is used to illustrate the benefits of separteness from the world. God's chosen ones survive. There is nothing in prophecy that indicates the "great tribulation" destroys everyone on earth except JW's.
The chosen one's discern the meaning of "the disgusting thing that causes desolation" and determine the opportune time to flee "Jerusalem".
Daniel indicates that quite a bit of the Earth's governments surive the clash of the King of the North (Beast) and it's rival the King of the South. Daniel 7:11,12 "I kept beholding until the beast was killed and its body was destroyed...as for the rest of the beasts, their rulerships were taken away and there was a lengthening in life given to them for a time and a season."
The fact that others besides the "separated ones" (whether JW's really are these or some other group???) survive are indicated in Daniel 7:14 "And to him there were given rulership and dignity and kingdom, that the PEOPLES, NATIONAL GROUPS AND LANGUAGES SHOULD ALL SERVE EVEN HIM." ALSO Daniel 7:27 "And the kingdom and the rulership and the grandeur of the kingdoms under all the heavens were given to the people who are the holy ones of the Supreme One. Their kingdom is an indefinitely lasting kingdom and ALL THE RULERSHIPS WILL SERVE AND OBEY EVEN THEM".
Governments and people will have to survive the catastrophe of the Great Tribulation, otherwise this verse couldn't be fullfilled.
The only entities that are thrown into the Lake of Fire during armageddon are the Wild Beast and False Prophet. Revelation 19:21 says "the rest were killed off with the long sword." The long sword doesn't picture eternal destruction as the Watchtower has claimed. Notice in Revelation 6:8 that Death and Hades (common grave) kill with a long sword. Those killed with a long sword get brought back to life. The birds, according to Rev 19:18 eat those slain with the "long sword". Among those slain are the "small ones and great"
These ones are seen again at Rev 20:12 "And I saw the dead, THE GREAT AND THE SMALL, standing before the throne and scrolls were opened...and death and Hades gave up those dead in them and they were judged INDIVIDUALLY according to their deeds." Justice is finally carried out based on the behavior of each individual... but during the judgement day AFTER armageddon.
If you believe in the Bible then you ought to be looking for a community of people who are separate from the world who might fullfill the role of "holy ones". Or you can ignore it all and get your day in court at some future time.