Nobody knows how much gold in the Earth else. So it is less predictive. Bitcoin is more clear. Therefore, it is more promising and its price will grow further.
I guess you are wrong. The geologists have already calculated the total volume of gold, which can be extracted. And the figure is around 70,000 tonnes if I am not wrong. Now taking in to account the 180,000 tonnes of gold which has been mined out till now, we can say that the maximum supply of gold is around 250,000 tonnes (i.e 8 billion oz.).