Each season events conspire, or are planned, that give unlikely people a chance to progress further in the game.
I don't think anyone was thinking Vee could win early on, but the switch and the alliances with N/P/K/S and immunitites got her to the final two.
There are a few Survivors that I really wouldn't give much of a chance of winning at this point e.g. Jan, Clay, Ken
What events could happen to allow them to porgress further?
(I don't Jan winning if everyone mysteriously dropped dead.)