 Ethereum used to be proof of work, but switched to proof of stake. Proof of stake is very different. The price of admission, you don't waste energy. You just have to put a little bit of money in collateral that you can lose if you are dishonest and spam the system. You just remove that whole element from the system. The Bitcoiners are religious about proof of work. They will never change. I don't agree with them. I think they should change.