I'm not sure that ends up disproving predictions of lower cost. By the Jevons paradox, more efficient steam engines led to steam-based eneegy being cheaper (yo

I'm not sure that ends up disproving predictions of lower cost. By the Jevons paradox, more efficient steam engines led to steam-based eneegy being cheaper (you need less coal per unit of mechanical power), but people kept paying about the same in total- just using more mechanical energy. So the equivalent would surely be electricity costs dropping, and people using more power (air conditioning, etc.)