Games in the Southeast are ^*&%&* HOT in September. During the Jags game FORTY plus people were transported for heat emergencies. I noticed that many left that game at the half. I'm betting it was the same in Miami and Tampa.
Aside from that....IMO....More n more, there are fewer hard core blue collar fans attending games. Fans that stay to the end. I have noticed over the last 15 years or so more n more fans leaving early and showing up late. Even The Swamp in Gainesville... There was a time I'd say you were crazy if you said fans would show up late for games against Tennessee and or FSU...but they do these days.