I don’t believe that goblins’ magical power could outsmart that of wizards in this way. Particularly with the emphasis on wizards having access to wands and spells.
But then goblins would still want wizards to bring in real gold for “minting”. And wizards would still steal or trade for all the Muggle gold to give to goblins, and billions of Galleons would be circulating as a result. And we don’t observe that.
I don’t believe that goblins’ magical power could outsmart that of wizards in this way. Particularly with the emphasis on wizards having access to wands and spells.
Also: why would goblins do this?
Because the goblins don’t like having real gold go out of their hands.
But then goblins would still want wizards to bring in real gold for “minting”. And wizards would still steal or trade for all the Muggle gold to give to goblins, and billions of Galleons would be circulating as a result. And we don’t observe that.