This is a sophisticated attempt to revive the old pagan notion of an eternally existing material universe.
Since the observable universe shows every evidence of having a beginning (no surprise to monotheists of any of the strains derived from the ancient Near East, but a great discomfort to atheistic materialists), the eternally existing material world must simply be unobservable, and partitioned into 'other universes' by states dense enough that the physics we can experimentally verify breaks down.
Notice that in doing this, the materialist abandons any rightful claim to being more scientific than the theist, since by definition 'another universe' is as unobservable as an initial divine fiat. Theism gains the advantage, though on the basis of Occam's Razor: one transcendant God is fewer unobservable entities than the infinity of 'other universes' this theory needs.
Personally, I quite like Hawking's null-initial condition proposal: there is *nothing* before the beginning, not even a 'before'. It's a nice mathematical model for a universe created ex nihilo, even getting the nihil right.
It's clear this universe had a beginning and its origins cannot be explained by those living inside it. To me placing faith that this universe came from another universe, where a different set of physics operate, and wherein the origins -can- be explained, makes more sense than an eternal God. There is absolutely no difference between declaring "God just was, He's eternal" and "matter just was, it's eternal".