What makes the 2020-W Proof Gold Buffalo in PR-70 so costly?

The population report doesn't indicate that the coin is more "rare" than several of its siblings whose prices are lower.
Is there an explanation that I'm not seeing?
1
The population report doesn't indicate that the coin is more "rare" than several of its siblings whose prices are lower.
Is there an explanation that I'm not seeing?
Comments
The 2020 proof coin is the current lowest minted coin in the set. The mint stopped short of selling the full mintage and pulled them early in 2020 with a mintage of ~10,500 out of the 16,000 max, creating the rarity. The 2024 coin with a current sales number of ~8,500 could overtake the 2020 as the key, but I don’t know how many remain in their inventory.
This coin was issued when the world was coming to an end - and many normal wholesalers/dealers ended up missing the issue.
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