BTC is not only the first coin but it has symbolic value for the entire crypto market, one symbol of the blockchain revolution.
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.
So there will be no altcoins that can replace BTC although ETH, Sol, Tron or Xrp... have utilities, applications and technologies that are far superior to BTC.
This is actually quite an important point.
I think platinum is rarer than gold and has more uses.
But gold is simply valued more because of its color.