It’s true that new altcoins can have a unique feature that Bitcoin can’t have because it’s already developed but other altcoin can’t copy the Bitcoin uniqueness which is the most important in cryptocurrency which is the real decentralization.
No coins can achieve it because all of them has a centralized control over the chain through the team that hold most of the coin supply which affects the voting for the development. Most of the project that has a DAO feature is just lying about complete decentralized mechanisms while the team itself has the huge voting power including other entities which invested heavily paying the team huge some of money during private investment.
Indeed Bitcoin is truly decentralized with limited supply and these unique features set it apart from other cryptocurrencies. You have raised an important about challange for the crypto enthusiasts to meet the same level of decentralization in other cryptocurrencies. It is also true that some altcoins may have unique features but most of the altcoin struggle to replicate the same level of decentralization due to various reasons, including control over coins supply and decision making processes. these are the main hurdles to achieve true decentralization.