Here's the problem.
You have 19 of the 20 contestants still in contention to win. Nearly half of those contestants have spent more than half of their time not playing the game (or, if you prefer, playing a very different game). One theory is that whoever comes back from "the Edge" will get most or all of the votes from the other persons who were on "the Edge." On the other hand, let's say Natalie or Amber comes back. What has she done to deserve a win? Well...I got voted out REALLY early, I won a single challenge to get back into the game and survived a couple votes (all the while having umpteen advantages that I bought with all of my fire tokens), and here I am. That person won't have made any enemies but also won't have made any "big moves." It's really quite absurd, and I'm also envisioning some sort of technical glitch with live reunion show.
One thing I just read is that, in September 2018 (less than a year before this season was recorded), Probst poo-pooed the idea of an all-winners season, saying, "We have 10 great winners that you’d want to see play again. We don’t have 20. We don’t have 18." Interesting that he changed his mind so quickly.