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/ )
A single bitcoin may be pricey, but fortunately there are eight decimal places after that first coin, enabling users to spend however much or however little they want.
You're right about the lightning network, it stands to revolutionize the bitcoin network by providing an instantaneous zero-confirmation payment layer on top of the bitcoin blockchain. Critically, though, it wouldn't work at all without the security provided by all that "wasted" electricity. Think of the lightning network like the HTTP protocol layer resting on top of the TCP/IP communication layer. HTTP wouldn't work without TCP/IP and TCP/IP wouldn't be nearly as useful without the myriad of protocol layers which it enables. This is still early times for bitcoin, and you ain't seen nothin' yet.