Didn't they say it wasn't Purgatory?
Apparently, they're saying the Island itself (and it's timeline including flashbacks and flashforwards) wasn't Purgatory, just the "flash-sideways" alternate universe!
But that, in and of itself, opens up a number of questions...
The only "real" people in the flash-sideways universe were the ones assembled in the church?
Why was Claire's child, Aaron, still a baby? He was shown as 3-4 before Kate turned him over to his maternal grandmother in the "real world". Did the grandmother kill him? (We didn't see Sun & Jin's child, Ji Yeon, indicating she was still alive.)
Where was the now-mortal Richard Alpert?
Who replaced Hurley as the Protector of the Island? (Ben Linus would've been the obvious choice)
Why did everyone look the same age as their last appearences together on the Island in the main timeline? Since some died after (perhaps long after) Jack died, wouldn't they look like they would at the time of their passing?
The upcoming 6th Season DVD set
Not since the end of the "reimagined" BattleStar Galactica
My head hurts...