You handwave physics away. Replacing copper with aluminium in an electrical motor requires in fact development of new motor, with worse efficiency. So motors an

You handwave physics away. Replacing copper with aluminium in an electrical motor requires in fact development of new motor, with worse efficiency. So motors and generators are going to be more expensive either way. Replacing conductors needs bigger conduits, etc. The copper piping is already being phased out in favor of plastics, roofing wasn't never really widespread, at least here it was used only on historical buildings. The grid has already been using aluminium whenever possible, including large transformers. Despite all that and despite perfect recycling, demand for copper is rising. It's diferent from batteries where there's still ample reserve between state of art and physical limits. So they can be easily substituted and price inflexed away.