As far as games is concerned, I'm taking a wild guess that Sony will be the odd one out when it comes to disc-media. With MS launching their next console this year, there's no way that they'll delay everything just to switch formats. Nintendo is wishy-washy as of this writing. First they announce Hi-def, then retract it. They did say that they'll use 12 cm discs. What's to say that isn't true?
As a whole, I'm still looking at it from a consumer's perspective. Why do I need more bleeding edge technology now? What good is these uber-discs without the hi-def tv and surround sound? With premium entertainment, there's a premium price that not everyone can afford.
I believe the PS3 will be pure Blu-ray at least when it comes to games. If nothing else, they'll flex their muscle just to say they did it. With the PS3 not labled as a pure game machine straight from Kutaragi's mouth, will this be enough to put Blu-ray on the map?
EDIT: I'm claiming ignorance here, but how would this hybrid unification idea work exactly?