I draw the line at adversarial wasting of energy. Bitcoin needs to waste energy for security. If humanity manages to produce twice the energy, bitcoin needs to

I draw the line at adversarial wasting of energy. Bitcoin needs to waste energy for security. If humanity manages to produce twice the energy, bitcoin needs to waste so much that the economic price of the energy to attack it is similar, so likely bitcoin would have to use twice as much energy to produce the same good. On the other hand, if humanity were to produce twice as much energy, your frappucino would still take the same amount (or less if the machines get more efficient somehow!), and would maybe even become cheaper with the cheaper cost of electricity. Adversarial proof of work is designed to not be able to become more efficient. It is designed to only operate in energy scarcity. Without PoW, creating a fusion reactor may mean energy is effectively free for everyone. With PoW, electricity must have a high enough cost that it deters attacking bitcoin, so anyone who owns bitcoin has a vested interest in wasting electricity until it is scarce and costs money again.