Earlier quoted context omitted.
Bitcoin is _not_ trying to go proof of stake because proof of work is the most secure consensus algorithm that exists. Proof of stake has some lingering unsolved problems, search for "nothing at stake problem" and "long range attack." All the energy consumed by bitcoin is a feature, not a bug. The only way to defeat the immutability of the bitcoin blockchain and do naughty things would be to expend _more_ energy than…
If that's the case, I'm not into it. It's not sustainable. What an incredible waste of resources. And presumably the energy cost correlates to the usage of the currency? How can it possibly become anything like widely used if it's so pricey? (Come to think of it, one way is the lightning network. Which doesn't use the blockchain for almost everything: https://lightning.network/ )
The peak energy cost is limited by the price of bitcoin though.