AFAIK most homes with poor insulation where build when energy in the US was dirt cheap (relative to the median income) and it was rational to save money on insu

AFAIK most homes with poor insulation where build when energy in the US was dirt cheap (relative to the median income) and it was rational to save money on insulation and just blast powerful AC (human effect on global warming was not known/established back then). Retrofiring insulation into already built homes is not cheap.