Why? I didn't start using more energy elsewhere when I switched to an EV or electric lawn maintenance tools. You think companies and people are using exactly as much power as available (or they can afford)?

It's a well-known "paradox" known as Jevons Paradox. Given enough efficient use of a resource, overall usage could actually far outpace the efficiency gains. E.g. use of coal got efficient enough that travel via trains using it became possible, which led to way more usage of coal.