A better technology than Bitcoin could emerge. What should we do if someone gives us a better system than bitcoin as a gift and leaves? It performs better than Bitcoin, and it even has the perfect decentralization of Bitcoin, which we value highly. Bitcoin was created in 2009, and now it's 2023. Cars made in 2009 cannot be better than cars made in 2023 or later. What if someone with as much genius and passion as Satoshi is creating a system better than Bitcoin?
You've raised a very good question and honestly I've never thought about this before. Just as you pointed out, the world is evolving everyday, technology is constantly been improved and newer products are developed as we've seen with automobiles, television, aeroplanes etc. However, since Bitcoin came into limelight there have been many cryptocurrencies that have sprang up, claiming to outperform Bitcoin. Most of them have disappear into thin air while some of them are in life support fighting for their dear life. So what I can tell you is that Bitcoin is here to stay and there's really not going to be any altcoin that will outperform Bitcoin.
A good question indeed about if another crytocurrency were to take over from bitcoin as the undisputed leading cryptocurrency, maybe bitcoin can still have it's relevance or it'd be relegated to being called "shitcoin". I sincerely hope that will not happen, because bitcoin has my respect, as the first and most outstanding crypto that has changed the narrative of transactions from banks to DEX. Another reason why i won't like another crypto to take the lead or be in pair with bitcoin in the crypto space is because, crypto in general might start to loose value just as other lesser coins are not worth much.
We live in a competitive internet age, where almost anything is possible, technological innovations are happening everyday. Individuals and firms are outdoing each other to give better versions of their innovations, so we'll just wait and see whether any any cryptocoin can take over from bitcoin, although I won't worry myself about that now.