Everybody can't be a king-priest. Who will the king-priests serve?
But it is correct that the number going to heaven is limited. Everybody can't be the "bride of Christ." The first resurrection underscores this since it occurs prior to the 1000-year reign of the kings and priests with Jesus Christ. Yet we see other people in the earth and not coming to life until after the 1000 years. Then too, the king-priests are judges of those who come back from the dead during the 2nd resurrection. So there are many examples that indicate those who become king-priests are a limited number and a much smaller number than the millions of people whom they serve as kings, priests and judges.
Having noted that though, please note a reference at Isa 6:13 to a tree being chopped down and the root remaining in it:
Isa 6:13 And there will still be in it a tenth, and it must again become something for burning down, like a big tree and like a massive tree in which, when there is a cutting down [of them], there is a stump; a holy seed will be the stump of it.”
Now, in the NT the kingdom is also represented as a tree, an olive tree, into which wild olive branches are grafted in where the natural olive branches were lopped off. So gentiles consider themselves to be "spiritual Jews" because of this. Even so, they are reminded not to become haughty since the life of the branches comes from the root of the tree which is made up of the natural Jews. That simply means while the Israelites were punished and had their seats in the kingdom taken away, a small remnant of natural Jews would still be part of the heavenly class and fulfill the Abrahamic covenant. In fact, they would remain the most important part of the heavenly class.
If we apply Isaiah 6:13 to tis olive tree, though, and assign the root of the tree to the natural Jews in the kingdom, and consider that the 144,000 is a reference to those natural Jews since they "master the song of Moses", then that would mean that the 144,000 makes up just one-tenth of the entire number, with 90% being from the gentiles. Thus the number is still limited, only it is not 144,000 but 1,440,000!
All that to say this: Those newly partaking ones may be quite legitimate.
When Christ returns, remember, a call goes out to come to the wedding feast, which represents the marriage between Christ and the elect. But many beg off. As a result, there is not enough to fill all the seats. So that parable tells us that the qualified number is not filled when Christ first arrives from among those invited. But rather than have the wedding feast empy, the master sends out his slaves to bring people from off the streets to fill the seats. These come from "eastern parts and western parts" meaning some of these are even non-Christians. Within the WTS, though, this would include invitations to some of those who consider themselves the "other sheep" and thus with the earthly hope.
All that to say this: On a high spiritual level, the master is trying to fill all these vacant seats that those first invited have not filled, so we expect that there would be an increase in partakers among Jehovah's witnesses right up until the end. The "great tribulation" begins when that last anointed one is sealed. The sealing of the elect has to take place during generally peaceful times and before the destruction of Babylon the Great by the U.N.
But also, in the parable of the vineyard workers, who work 11 hours, this is a reference to the WTS. Each hour represents 7 years and thus the work is carried out for 77 years from 1914-1991. But notice the ones first in the work are guaranteed a penny. Those coming from the 3rd through the 11th hour are expecting less. Within the WTS, all the anointed are those first in the work. The third-hour workers would begin to show up after 21 years (3 x 7 = 21). Add 21 years to 1914 and you get 1935, the year the "earthly class" was officially recognized. BUT... note that during that last hour, the 12th hour, which would be from 1991-1998, where the workers are paid from the last to the first, that ALL THE WORKERS GET THE PENNY! So technically, all the "other sheep" earthly class were invited to be part of the kingdom between 1991-1998 anyway! So while there is a two-class system confirmed by the Bible among witnesses from 1935-1991, after 1991 there is just a one-class heavenly system again, where all the workers are given the "penny" which represents the heavenly calling.
Now, there should have been a huge surge, one would think, in partakers after 1991. But those who came in first were more aware of the second coming occurring in 1992, which means Christ's first passover after his return occurred on April 6, 1993. Even so, his return would "end gift and sacrifice" in the middle of the 70th week (1989-1996) and thus would end the need for the Lord's Supper celebration. So while there indeed was a huge increase among the other sheep after passover of 1993, it would not become readily obvious because they knew better than to continue to celebrate the Lord's Supper. They don't partake. Even so, we started to see an increase in those who felt they were ofr the anointed and being still associated with JWs did begin to partake. So those new ones who do partake are not second guessed.
Reflect on the parable of the prodigal son. The prodigal son is the son who becomes the Christ and his father gives him a private banquet. The older brother which repreesnts the first ones in the vineyard work and thus the original anointed ones, complain about this when they hear about this banquet given to their younger brother (one of the "other sheep") who has now become the messiah. Those who are part of the banquet are in secret, the older brother is in public. But even though the older brother murmurs against the younger brother like the first-hour workers murmur against the 11th hour workers, he is not rejected. The older brother is not rejected. He did his duty. The father comes out and assures him, "what is mine is yours" -- just as the master of the vineyard tells the 1st-hour workers, "take what is yours and go!" So there are two classes of anointed ones. Those who are in public and those who are in private. Those in the secret societies who are part of the banquet do not partake of the emblems at the Lord's Suppre, even if they are pretending to still be active witnesses. But others who become of the anointed who are not part of the secret banquet, would be part of the public class and they may still partake, if only to demonstrate that the number of the heavenly class is increasing and some are still being sealed into the kingdom.
Sp evem those who know Christ returned in 1992 and ended the Memorial in 1993, we still recognize that some might still partake and still be legitimate anointed ones, since they would join the other public anointed ones with JWs who are still partaking.
So this is really good news! This not only suggests that there were a few empty seats still available as late as last year, but that because of these last few empty seats, Armageddon and the great tribulation has been delayed! It has now been some 20 years since the 2nd coming on December 25, 1992!
ANYWAY: If you still believe the Bible and believe Jehovah is real and Christ is real, and you feel that you have the heavenly calling, then you probably DO! It means Jesus is knocking at your door. But you've got to get up and answer! You've got to study the scriptures to know that there will be seats right up to the last minute when the "great tribulation" begins!!