A myth? Really? As a "Northerner" who fled south for college and has since returned, I have been fortunate to see my fair share of football games in both "climates". I will say that while the conditions can get a bit nasty in the south w/ the 40 degree temps, rain and wind which you speak about, but they do NOT come close to comparing with the miserable conditions football is played in up north...
I have been a season ticket holder for the Ravens for 8 years and have sat through weather conditions that can make grown men cry in and around the North East. 40 degrees and rain stinks. We get that in September. 25-30 degrees with 25 mph winds and freezing rain is flat out miserable.
We get this from December on; and Baltimore really is not that bad compared to NY, Boston, Buffalo, Cleveland and Green Bay, etc. I prefer the snow to freezing rain any day of the week. You just can't escape the wet stuff.
One question... When has this ever happened in the south (Buffalo 12/2008 - Winds 40-60mph, )