The overhead (not underground) service entrance wire that comes into houses is a conbination of aluminum conductors and aluminum-clad steel conductors. The two insulated wires are all-alluminum and the bare wire that is the neutral conductor is aluminum-clad steel. It is so because the aluminum-clad neutral is the one that physically supports the other conductors that are spiraled around it. Almost all wire used by electric utilities now is all-aluminum or sluminum-clad steel.

I certainly agree that copper tube in the finest thing for water supply pipe in buildings. It is well proven. No scale ever builds up inside of it. The inside is very smooth giving low flow resistance. It is rugged and never corrodes away.

As to contact wire, I think it will always have to be copper (hardened copper for wear resistance.) The parallel feeders will be aluminum