That’s incorrect. Aluminium is about 30% worse by volume than copper, meaning you need to go up a size. What stopped it being used for houses was that the terminations weren’t good enough, because aluminium has different thermal expansion and corrosion properties, plus they were using much worse alloys. That’s now mostly fixed and if you’re in the US, there’s a very good chance that your service main is aluminium, and there’s talk of allowing copper-clad aluminium (CCA) for subcircuit wiring.

Per mass, aluminium is a better conductor, which is why it’s almost exclusively used overhead and in pretty significant volumes underground. The power grids were built on ACSR.