I don't think it would be a great idea to think about gold losing its value, because for me, there's no way people would sell gold for cheap market price, it isn't like bitcoin that the market price solely depends on the demands that it has. My idea is like this, since they are both valuable, an investment could be backed by investment as well, so why not use Gold to back bitcoin up in the market? With this, the value of bitcoin will be even higher considering that a great asset is supporting it.