I think the Bible is more literal than JWs think, I think that all the people who survice the coming Tribulations will continue to live as Nations today, but they wont have Satans bad influence.
So far there has never been a test to see if mankind can run himself happily independant of God AND Independant of the Devil.
It is these Nations that at the end of the 1000 years try to storm Jerusalem, its not a final test of Christians like the JWs say, nowhere does it say that.
Christians on Earth will live in Jerusalem, maybe with Ezeikiels third temple with its river of water of life, outside will be the failed Christians, unable to get in so they will still be with the nations, they will literally be weeping and gnashing their teeth, not figuaratively.
Iam unsure about Isaiah 65, maybe this will apply to people of the nations?, life will certainly be better without the Devil and his bankers enslaving us, if the Christians in Jerusalem have access to the waters of life, why would they die after 100 years?, unless the third temple comes after the 1000 years, but I dont think the disciption matches with the New Jersualem temple?