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.
We can't say bitcoin is far superior in all cases. Maybe superior when it comes to decentralization and security. Other than that, it is just a coin that people hold or use for making payment. But the value is high because it is "Bitcoin". It is the first crypto currencies that was made/invented. No matter how good other altcoins are, people will always in the end hold some bitcoins because believe in bitcoin and its future. Think of it like this, bitcoin is the leading all other altcoins. If bitcoin fails, there is a high chance the whole market will fall because people will lose faith on crypto currencies.