you shouldn't even be comparing bitcoin and gold because they have nothing in common and not in the same category for one to replace the other. bitcoin is a currency and gold is many things but not a currency. gold will remain as it is as long as it keeps its use cases which it will. and bitcoin, as a separate and entirely different thing will grow only as long as it is offering what it is suppose to, meaning a decentralized secure payment system that is censorship resistant.