I disagree. And sure that architecture is still in good condition but that was before the invention of HVAC and the temperature delta between the pressure systems is now much higher than it was during those periods. Besides stone and concrete is mostly an air barrier and is a much better air barrier than the typical buildings put up in 40’s-00’s with just substrate and fiberglass. Masonry buildings put up during this time are also in good shape.

We’re talking about the majority of malls/commercial buildings that have been left to rot.

I think it’s like 80 percent of commercial buildings have mold problems and water damage that were built during this period. I’d reckon the 20 percent are the masonry buildings.