I feel like in the endgame they need to develop a use for wood/iron/stone. Right now in the endgame there is only gold... this will cause a lot of problems down the line (Endgame players will have an insane surplus of wood/stone/iron and just flood the market with cheap resources creating more and more endgame players).
Basically you need to find a wood/iron/stone resource sink in the endgame.
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Sorry! Kong doesn't provide it.