The idea that only JWs will survive Armageddon is just another delusional false teaching of the apostate "evil slave." The WTS is the "evil slave" in fulfillment of propecy, also the "man of lawlessness" and the "false prophet."
BUT, if that's the case, it is still only one slave out of TEN SLAVES that were sent out to do work! Normally, the WTS has the context of calling itself the "slave" and it is in charge of an entire organization. That means they can't explain the other 9 slaves not being in charge of their own organization. Suddenly, the slaves have to be individuals within the WTS? Ridiculous.
So just by this reference, we know the witnesses are not the only ones who will survive Armageddon, if in fact, the majority of them will actually considering the GB is now apostate and most of them are worshipping a false god via them.
"Have no fear little flock" is a reference to the faithful witnesses in the organization. They represent the five "wise virgins." So that alone, when applied to the WTS shows only half the anointed make it into the kingdom. Thus Jehovah would not consider many witnesses as true Christians; they are weeds and not wheat. They love the Watchtower more than the Bible itself. But with respect to the "little flock" we clearly she that Christ says he has "OTHER SHEEP NOT OF THIS FOLD." Again, you have evidence in the Bible that Christ is gathering his elect from more than one place and the primary place is not the WTS. The WTS only produces a "little flock" which is removed and brought to other sheep from another fold and obviously a larger flock.
So no, Jehovah is not going to destroy everyone except witnesses.
On the other hand, the millennium is a very special time and per my understanding, likely 1/3 of the population, who will want to maintain their own rule, will have to be destroyed at Armageddon. Another third might survive Armgaeddon but still don't qualify for the millennium and so will die off of old age. That will leave 1/3 of the survivors of Armageddon who will make up the populace of the new government under Christ. But also note, all those who do die at Armageddon or who are not chosen for the millennium will come back after the millennium during JUDGMENT DAY and then be judged.
The rule of thumb based on how many angels, fully knowing God, but who still rebelled, will be reflective of those on earth as well. That is, 1/3 will choose not to live under God's rule by Christ. Two-thirds of mankind who were born will enjoy everlasting life on the earth. Two-thirds not making the grade for the millennium is based on Zech 13:8 where in the case of the Jews, two-thirds pass through he fire and are killed. This is fulfilled during the Holocaust. That same percentage will likely be applied to the world, where two-thirds are destroyed and one-third remnant is selected for the special time of the millennium. Note that contrary to WTS false teaching, no one will be resurrected during the millennium!
So while 99% will not be destroyed, 66% will and that's still a large number. But some of those will get everlasting life after Judgment Day. So in the big scheme of things, 2 out of 3 people will get eternal life and Jehovah is only destroying one-third of the world's population who probably choose self rule and thus reject rule by Christ in a multi-cultural world where no one is rich with a lot of servants.
LS