Ethereum is not the fastest and most perfect system, and there are still many problems in their but ETH is a platform that is used the most. Beside that, in term of decentralized section, ETH is only second to Bitcoin and it's extremely hard to attack 51% into ETH system. In the other hands, their ecosystem is developed by the biggest community and be approved by many big investment funds. As a result, ETH almost cann't be replaced and beat beside Bitcoin.
They are both like kings and queens who are very united until now. everyone is still using it today as a means of transaction in all countries. so it's hard for me.
Ethereum is very useful in the crypto world, and is very influencing,
because Ethereum's market cap is the largest of all altcoins, this makes Ethereum the nickname of the king of altcoins,
but for me Ethereum has not been able to become the next bitcoin.