Demand side response drives up costs a lot. You end up with expensive, rapidly depreciating capital equipment sitting idle and not earning any revenue. The same problem applies whether the equipment is a GPU cluster or aluminum smelter. If we're going to have a modern industrial economy then we need to have enormous quantities of cheap electrical power available 24 hours a day.

Long distance high voltage transmission lines can help to an extent but create the same sort of concerns about dependence on unreliable foreign countries as fossil fuel imports.