bitcoin was never supposed to replace gold and it is not even designed to do anything like that simply because bitcoin is a currency while gold is a metal that is used for other things including an investment but never as a currency anymore.
as for only the profitability and the investment aspect of the two bitcoin has already entered investors' portfolios as an investment to diversify while making a lot of profit. i wouldn't call this "replacing gold" but it is pretty similar.
indeed bitcoin was created to improve the existing financial system by cutting time and costs in transactions, and bitcoin was created to replace the role of physical money which are monopolized by the government, but after bitcoin is getting hype and high prices, many people think that bitcoin is very profitable if it's used as an investment instrument so that until now bitcoin was made an investment