There's is no way that an altcoin will overtake bitcoin. Bitcoin is the mother of all altcoins, even ethereum cannot win against bitcoin.
It seems that everyone understands it already. The October 2020 statistics says that now, 20% more people became BTC hodlers. This is a proof that most people dealing with cryptocurrencies are absolutely sure that Bitcoin is the crypto market base. It dictates the rules of other alts behavior.
Until now bitcoin is the better cryptos but we never know what we are going to see in the future.CBDC can be a bigger threat for the decentralized cryptos if every government starts to roll out them before the adoption of decentralization because people are still ignorant about centralization and decentralization.