Just like gold, there are thousands of metals produced such as steel, aluminum, silver, etc., which are widely used in daily life. but gold has always been the most valuable metal, still number 1.
That is right about gold but also know that Bitcoin has a dual application use unlike gold or any other metal, bitcoin is a digital store of value and serve as a good source of an investment assets, the two has been the most leading asset for store of value and Investment in general.
What about gold and other metals? They can also do what btc can do but the only difference is that bitcoin is digital and precious metals are physical but anyway it is not about between gold or other metals but it was about the btc and altcoins. No alts can replace btc because alts are not the same as btc, alts are alts and only alts can also replace an alt but I think it's also on the way how people think.
Someone can use an altcoin and thinks this altcoin is better than btc, so he will never use btc anymore. He literally replace bitcoin there but to the majority that loves bitcoin, no matter how good an altcoin is, we will always consider bitcoin to be better than them.