In my particular case I'm renting a house, so it is probably more directly important to the landlord to insulate the house than if it were a large apartment building. The resale value for the house goes up steeply with well-insulated windows. Also the quality of life inside the house improves with better insulation and can therefore potentially draw a slightly higher rent. Also the landlord will have to replace the AC and heating unit less frequently, and those things are expensive.
However there are also indirect benefits to improving insulation generally. First of all there is less fossil fuel pollution since much of the US is still mostly on fossil fuel power, so reducing electrical demand has a positive impact on air quality and atmospheric carbon dioxide. Also a lower load on the local power grid reduces operating costs and reduces wear on grid equipment, reducing frequency of part replacements. Also AC units tend to be pretty loud since they're running fairly large compressors, and themselves generate heat outside the house, and though these factors may be small they do contribute to both noise and heat pollution.
I think a subsidy for energy efficiencyizing buildings in various ways should be provided, I know they have been in limited ways before. Regulating new construction to ensure a base level of heat exchange resistance would be another way.