However, one could argue that a proof of stake Ethereum (for example) would still be worth as much while at the same time drastically reducing the amount of CO2

However, one could argue that a proof of stake Ethereum (for example) would still be worth as much while at the same time drastically reducing the amount of CO2 emitted. So if we measure it that way then moving away from proof of work should be the way to make everyone happy? No more crypto miners buying graphics cards, far less CO2 emissions, crypto retains it's value since most owners don't really care about how it is made anyways and only see it as an investment opportunity.