The numbers are not hypothetical -- they are based on verified auction results and completed eBay sales accessible to anyone
The cost of cards vary, with common cards being much cheaper than Illustrative Rares, and Immersive Cards being the most expensive

Ifrit 33%inclusion 31%synergy 5.61K decks 17.2K decks Summon: Primal Garuda 32%inclusion 30%synergy 5.67K decks 17.8K decks Dryad of the Ilysian Grove 29%inclusion 17%synergy 5.25K decks 18K decks Jill, Shiva's Dominant 27%inclusion 25%synergy 4.86K decks 18K decks Destiny Spinner 25%inclusion 21%synergy 4.57K decks 18K decks Satsuki, the Living Lore 25%inclusion 22%synergy 4.50K decks 18K decks Summon: Leviathan 25%inclusion 23%synergy 4.45K decks 18K decks Ignoble Hierarch 24%inclusion 13%synergy 4.29K decks 18K decks Yuna, Grand Summoner 24%inclusion 22%synergy 4.27K decks 18K decks Summon: Fat Chocobo 22%inclusion 21%synergy 3.86K decks 17.2K decks Bloom Tender 22%inclusion 4%synergy 4.01K decks 18K decks Yenna, Redtooth Regent 22%inclusion 19%synergy 3.97K decks 18K decks Zur, Eternal Schemer 22%inclusion 18%synergy 3.87K decks 18K decks Anikthea, Hand of Erebos 21%inclusion 19%synergy 3.78K decks 18K decks Noble Hierarch 20%inclusion 11%synergy 3.60K decks 18K decks Clive, Ifrit's Dominant 19%inclusion 18%synergy 3.43K decks 18K decks Sigurd, Jarl of Ravensthorpe 19%inclusion 17%synergy 3.41K decks 18K decks Summon: G.F

I expect some great spec targets here once we know the whole set, though
People will pore endless hours over set reviews, Modern breakouts, and Reserve List buyouts, but there is, comparatively, nothing written about foreign foils and obscurities
Fakes will not have one