Passing gold is really not that impossible at all, we just need to be about a million dollars, and reaching that price isn't that unlikely for us at all, it would just require some time. However, during that period, gold wouldn't stay the same neither, would go up too, and that's why bitcoin wouldn't be number one after it goes up x10, it would require to go up a bit more.
However, the pace of bitcoin growing, outpaces golds increase, so that means eventually we are going to reach there, its not going to be impossible. We need to make sure that we can get a better return and wouldn't be this high. We should consider the possibility of making some good return. If we want to make sure that we can hold it long enough, then we may reach number one all together.
There is no denying bitcoin is a very fast growing, but it would be a poor comparison to compare the growth rates of two assets with very different capitalizations. Because typically small cap assets will always grow better but as they get bigger, the growth rate slows down.
Instead of just looking at the price, look at the market capitalization of BTC. Based on its current market cap, bitcoin would need at least another 20 trillion to equal gold, while it would take 16 years to reach a market cap of 2 trillion. How long do you think it will take for BTC to reach 20 trillion at the current growth rate? Things seem more difficult when viewed this way, don't they?
So you're not wrong to say bitcoin has the potential to surpass gold, but you'd be wrong to think it's easy.