Human nature does. We're like a gas, and we fill to expand the space we're in. If technology uses less power, in general, we'll just use more of it until we hit whatever natural limits are present. (usually cost, or availability) I'm not sure I'm a proponent of usage taxes, but they definitely have the right idea; people will just keep doing more things until it becomes too expensive or they are otherwise restricted. The problem you run into is how the public reacts when "they" are trying to force a bunch of limitations on you that you didn't previously need to live with. It's politically impossible, even in a case where it's the right choice.