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.
Bitcoin is considered the pioneer and founding coin of all cryptocurrency. Among all other coins, bitcoin stand out the most because of its features that others don't have such as its volatility rate, decentralization, its uses, and its competency against the flow of time. Which is why most often people say that bitcoin already withstood the test of time, in which most coins in the same timeline with bitcoin didn't survive.
Personally, I think there would come a time that bitcoin will have its greatest competition and probably has the possibility to lose the spot of being the top 1 above all. However, I don't really see it happening soon because as of now, the coins might be competitive, but it still lack on some part and its innovation still needs improvement. Those coins in par with bitcoin could possibly be the center of the light in the future, if they would surpass all bitcoin has to offer. Although, i think it would still take a long time for that, and bitcoin will still continue to reign despite all soaring crypto coins nowadays due to nice projects and background.