I do not think, that China goverment can buy gold mines around the world so easy and start to stocking in gold. Gold mines are rare around the world and find one, which you can buy, would be very hard.
i think they will end up producing it in the future, because it's rare like you said and it's not convenient to buy it at this point, because it's also very centralized and i assume that buying one will not return the cost in a short term and not even in a long term