The theory goes that Sony's play is not for the next generation games market at all. Microsoft's Xbox 360 is no more than an irritating diversion. The big play is for the high definition DVD market, and in this context, an early launch, with small hardware numbers and threadbare games software support might just be a good move.
This play potentially represents Sony's most important move in its entire history. Imagine; a royalty for Sony on every single DVD sold between 2006 and 2012 or thereabouts. No wonder Bill Gates hates Blu-ray.