OP gold and other metals are their own market. Bitcoin and other cryptocurrencies are also their own market.
The thing is though that if Bitcoin eventually fulfills the objective of Gold - a stable store of value - then why would someone buy Gold?
People buy Gold, not because it is shiny, but because it holds its value compared to fiat, which has inflation.
If Bitcoin can offer this at a superior level to Gold (when Bitcoin eventaully has a higher Stock to Flow Ratio) then people will likely start opting for Bitcoin instead.
I believe each market will have its own niche in society. Gold found its niche, Bitcoin will too. But I don't believe one will kill of the other because the other one is "better", liquidity will only shift from Gold to Bitcoin, and Bitcoin to Gold cyclically.