We expected it to have a bigger dampening than what we saw. I'm not an entomologist, so I can't claim to be an expert witness on beetle biology, but the explosion of numbers has led to a change in the biology of the beetle. Its capacity to adapt to changing circumstances has actually increased a lot because of the numbers, so this particular plague has not gone away.
The scientists are pretty consistent on three things. Part of the problem with the beetle is fire suppression. If there weren't so much juicy timber there, they wouldn't do as well, but nobody wants to see huge fires.
It is the traditionally very cold weather in the early fall that kills them off, but partly the scientists are consistent in saying that it hasn't behaved the way they expected.