I've seen enough to say that the reason we drop away in second halves is almost purely psychological. We are simply up by so much that it's hard to be motivated.
Brisbane aren't a good side? They've beaten Geelong, Essendon in Melbourne and of course won the NAB Cup. They pushed Adelaide and West Coast really hard as well. We smashed them.
I put our poor second halves down to the fact that Pendles and Swanny have had to do the bulk of the midfield work in the absence of Beams, Ball (for the majority) & Thomas and they understandably tire. I thought the Bulldogs game in particular was played at such a quick pace in the first half that it was always going to be hard to keep it up. Hopefully with the inclusion soon of Beams, Young, Goldsack, Ball, Krakouer etc we will have our rotations back to where we can give everyone the perfect mix of game time and rest and the 4 quarter performances will start taking shape.