I'm also a bit confused about Egan's problem with his theory:

I think the universe we live in provides strong empirical evidence against the “pure” Dust Theory, because it is far too orderly and obeys far simpler and more homogeneous physical laws than it would need to, merely in order to contain observers with an enduring sense of their own existence. If every arrangement of the dust that contained such observers was realised, then there would be billions of times more arrangements in which the observers were surrounded by chaotic events, than arrangements in which there were uniform physical laws.

Isn't the point that there is more than one level of infinity? That the 'density' of events determine how likely we are to experience them? That's what measure is, as I understand it. So it seems that Dust Theory has the opposite problem- our universe is much more complex and contingent on highly improbably factors than it would need to be to contain observers.