They don't support blu-ray because they don't want to advantage Sony, even if not in the gaming department. The same goes for Microsoft, why did they suppoerted HD-DVD? They do not own any format or any film company. It was just because they didn't want Sony to succeed. It is clear that all the blu-ray thing on Ps3 was not meant for gaming, in terms of gaming the blu-ray (despite what some sony developers say) has been a problem it increased the hardware cost and it delayed the console launch, also I've yet to see a multiplatform game to be canned due to DL-DVD limitations. But blu-ray is the core of Sony overall strategy, they use it to sell movies, to sell HD TVs, now to support 3D products. It's clear that both Nintendo and Microsoft as direct competitors doesn't want to support that. Also, using an uncoventional format, is supposed to be a good way to fight piracy.
As for DVD, it may simply be an image issue. Releasing and HD console in 2012 that actually only supports SD content will make it look outdated, so they just say its not a device meant to be a movie player. The DVD wouldn't be a selling point anyway, (thought blu-ray is another story). I just can't imagine an HD TV standing in a living room still without a DVD player.
That's not to say I'm happy with their choice, btw.







