I agree with your opinion, Ethereum has an excellent growing ability, if you look at Ethereum past history then you can see the successful journey of Ethereum. I believe ETH is the best crypto coin next to Bitcoin.
It's actually not quite right to say that we will replace ethereum because of the fact that ethereum is an altcoin with high trust, but replacing bitcoin is wrong because until now no one can replace bitcoin as an investment that many people like. Ethereum as a high-confidence altcoin has now experienced a big increase