Did a little reading about proof of work this morning, and my conclusion is that we're 100% ****ed as a species, thanks to blockchain.
Basically blockchain advocates will tell you that PoW is not inefficient. Their reasoning is that blockchain converts energy into "security", and the more energy that needs to be spent, the more secure the outcome.
Blockchain is most secure, they say, when the energy used to create hashes tends towards 100% of all human energy used. Because then there is no energy left to attack blockchain (lol).
The goal of Bitcoin and other blockchain implementations IS NOT to reduce energy cost. They don't see it as waste. They don't want to compare with non-blockchain technology (that's been around decades and doesn't waste energy quite so profoundly).
Instead, blockchain advocates see a future where blockchain uses all the world's energy, and in return provides "security of blockchain".
It's the most bizarro pseudo-religion you can find. Worse probably even that Scientology.
They don't see consumption of energy as a problem - they actually want MORE consumption of energy and resources, until blockchain is using everything we can produce! And that they see as a good thing... it's ****** up.