If you look at the players when was the last time that was true? When was a Minnesota team mostly Minnesota farm boys who may not have been very fast, but were tough and could make holes big enough for their slowpoke running backs to hobble through?
Most of the top players come from a few states like California, Texas, and Florida which have well developed farm leagues in their high school systems.
As Jerry Seinfeld once said, the only thing that doesn't change much about teams is their uniforms, so basically we're all just cheering for laundry.