There was a time in the WTS history that all its baptized members were anointed because that was the only choice. Then in 1935 the WTS made it official that not all would be anointed, some would stay on earth who attended.
I remember one older sister telling she was so relieved because she never felt anointed and wanted to live on earth, but that was not a choice.
For the first 3 years, only the anointed were invited to the memorial and then in 1938, the great crowd were invited as observers only.
The WTS has also said that eventually all the anointed would be dead and in heaven and the need for the memorial would end, so it would no longer be observed. And that through some supernatural means, everyone on earth would know the names of every individual who made it to heaven, the 144,000.
Recently, the WTS has said that all of the anointed must be in heaven shortly after the great tribulation for the marriage of Jesus and the bride of Christ. That seems to indicate that if the end is soon, that some of the new anointed will have to die of less than natural causes.
I have seen posters on JWN voice their suppositions with some anonymous source. But this is further out than those. But the WTS doesn't need a realistic scripture; just do what some people outside the WTS use for every occasion, John 3:16.