Blu-Ray trumped HD-DVD, but it is getting the shit kicked out of it by regular DVDs. People don't see the logic in having to fork out for a shitload of expensive new equipment, then replacing their existing DVD library with vastly overpriced Blu-Ray versions for an extremely minimal improvement. Even bundling the Blu-Ray player with the Playstation 3 (currently a distant third behind the Wii and XBox 360 respectively) hasn't made the expected dent in the market.
As for streaming them...fuck that shit. My connection is so slow (due to my location) that tube sites are very much a hit and miss affair for me. A HD file just wouldn't work out...best case scenario would be like watching an episode of Max Headroom in slow-motion.
Besides, why waste money on HD now when NHK in Japan are already doing test broadcasts in UltraHD?
I'm quite happy with my standard definition DVDs, thank you very much.