I was thinking the same thing. However back when the NFL wasn't the big deal it is today a lot of the stadiums were located right in the downtown areas. I know there are exceptions but aren't most cites set up on N-S & E-W grids. This would have made NW-SE configuration more difficult. Also a lot of them were combo football-baseball with baseball being played in the summer with the sun straight up.
I guess that’s why they switch goals every quarter. The Sun and wind factor................