So obviously one day it will be replaced.
But I don't think that future is any near.
Gold and other precious metals, up to this day, are still being used somehow as a currency. They still stand to what they were before but it's just that many people or countries in the world opted to go for fiat and build their own currency. But still, again, up to this day people would still accept gold as a form of payment. It is not replaced totally, it's just that there is a more convenient and easier option that was invented after it.