The question isn't whether gold is a better growth investment than the highest flying stock you can think of, or even of the Dow over a long period of time.
The question is whether it holds it's value better than fiat currency. The example above shows it does.
BTW: The above example assume zero nuministic value for the gold currency.
The right question is a function of what one's goals are. If the goal is to identify a superior unit of account, store of value and currency, then indeed your question is the right one. However, if the goal is to trade from one position to the next over time so as to maximize the value of one's trading account, then one can do better than "buy and hold" in any single asset class.