Thin foil can block massive amounts of heat transfer, but it needs a massive temperature difference to be effective. So, insulation sort of makes radiant barriers irrelevant.
As houses are built tighter, they exchange less air between inside and outside. This saves energy, but the inside air can get stale if you don't have a fan and a plan
A snowball effect of physics vs. physical structures: water carries salt to the surface of masonry, which crystallizes and can blow apart its masonry host.