I think this is not what the parent poster was saying. The problem of bitcoin is not one of induced demand, where cheaper goods means that people become willing

I think this is not what the parent poster was saying. The problem of bitcoin is not one of induced demand, where cheaper goods means that people become willing to use it less efficiently. Difficulty adjustment is as if every car monitored its MPG and then dynamically adjusted the engine until it became as efficient as a 2003 hummer. When the mining efficiency is increased, that isn't translated into more bitcoins being mined or more people benefiting from bitcoin. The matching mining difficulty increase ensures that all that extra efficiency will be turned into waste heat.