Yes true. Cardano will never act as an alternative to Ethereum. Ethereum's ecosystem is strong enough and neither cardano nor Solana is likely to achieve the same popularity as Ethereum. So I think it's unfair to compare cardano with ethereum. But we can see SOL as a bit of an alternative to BNB but not from the blockchain side but from the marketcap side. Because SOL marketcap is almost on track to surpass BNB
Cardano will never be a replacement for Ethereum. Many may think that Cardano can overtake Ethereum and those who think so I think are wrong. As we know Cardano is Decentralized Proof of Stake Blockchain and Ethereum is Decentralized Blockchain. Ethereum coins have smart contract functionality. In terms of market capitalization, the position of Ethereum coin is after Bitcoin.