The Falcons attendance is fine.
For a playoff/good team, their attendance is terrible. They are definitely in the bottom half of the league. I've been there for a prime time game vs the Saints, and it was filled with Saints fans. They were also playing to lock up the #1 seed and NFC South in this game (2010).
I don't recall the 'Aints attendance being all that great before your lonely little Super Bowl season.
They sold out the 06 season, before a game was played. No one knew if they would be a good team. The season before that they were 3-13, and playing every game including home games on the road because of Katrina, but it still sold out for the following year. Even when the Saints had shitty teams, and we've had plenty, people still went to games.