The most important reason for Ethereum's success is that Ethereum's smart contract adopts Turing complete technology, which makes the function of smart contract very powerful, and gives birth to popular application innovations such as ICO, defi, NFT, gamefi, etc.I think bitcoin has not changed and may not need to change.
This is the reason bitcoin is a currency whereas ethereum is not. Ethereum may not remain powerful when another platform with advanced features will be developed. No one could argue there would no chances for new technology to be invented to replace ethereum as litecoin was the leader in altcoin space and it was replaced by ethereum by providing new applications through smart contracts.