Increased demand for homes can be handled by adding more transformers. The lines are fine, but the number of homes per segment behind a transformer needs to be reduced. This is already ongoing in Germany for example.

And the switch from incandescent to CFL/LED did save a lot of energy in total, both for residential and business applications. I once read the number that the net load was reduced by 1 GW due to the change. That is a reasonably sized nuclear power plant.