I know of these projects and some of my friends are investing and/or building them. I commend the ambition and really hope they one day turn into something grea

I know of these projects and some of my friends are investing and/or building them. I commend the ambition and really hope they one day turn into something great. That's beside the point, though. Knowing that Ethereum and Bitcoin consume more energy than Iceland and Switzerland respectively, why don't we turn them off until they're providing actual use? I get that markets need time to figure out if a product is useful and useless things get built all the time, but has that discovery process ever been done at this scale before? For instance, if proof-of-work ends up spending as much electricity as the United States and we still can't use it for anything meaningful, shouldn't we be concerned? I know "turn them off" sounds silly, but you can tax the miners or impose energy consumption caps until there is a smart contract out there that is arguably benefiting society. If concern for humanity's wellbeing on this earth is a "throw away" concern to you, then maybe you can provide an argument for why everything's going to be OK? Have we fixed global warming and I just didn't get the memo?