I am curious about whether intangibles- especially homefield advantage, but (somewhat related) warm weather or indoor teams playing in harsh conditions, etc as well... play a part under the hood.
Being a Raiders fan for a very long time, for example, I recall several heartbreaking losses when I was a child that seemed related to the warm California teams travelling late in seasons or in the Playoffs, to New England, Pittsburgh, Kansas City, and Denver to play important games in the snow, or in difficult to hear conditions such as Seattle's dome.