Not to worry about the source material; outside of porn, not much is shot on video.
The film camera's most movies use has much more resolution than even the highest current hi def tv formats. Lucas did shoot the newest Star Wars prequels with HD video cameras, and likely the future will one day belong to video as opposed to film. But we're not there yet.
I don't see how anyone can really answer your question with confidence I'm afraid. DVD was a such a huge success because is was a quantum leap over videotape, in all ways. It's got better a better picture, better sound, is more durable and doesn't need rewound. DVD was head and shoulders above anything most people had ever seen and represented a change in the way the public viewed movies at home.
Neither HD-DVD nor Blu-ray represent that type of paradigm shift. Sure it offers a better picture for those with an HD set, but it's essentially still just a DVD. In a sense it's a victim of the DVDs success, much as SACD & DVD-A are victims of the CD's success. The unprecendented flexibility, durability & convenience are the big draw for consumers, and DVD already has that.
Plus, DVD already had a foot in the door before any serious challenger came along (once DIVX tried to compete it was already too late, although it probably delayed the ascendencey of DVD by at least a year). With HD-DVD vs Blu-ray, potential customers know they'll be treated to a
format war right from the start. With only 20% or so of American homes having an HD set, both sides are gonna need the fence-sitters to commit pretty quickly.
I'd say there's almost no doubt that
some hi def DVD format will succeed, but which one? Microsoft is backing HD-DVD, and they're a huge company. Still, Disney & Sony are committed to Blu-ray. In fact, the Playstation 3 will reportedly feature a Blu-ray drive. This is shaping up to be a clash of the titans.
I'm the quintessential "early adopter," but this is one war even I might sit out. Unless someone comes up with a universal player that will play both (plus all the 'white elephants' of the past for good measure), I'll sit back and hold my fire til I see the whites of their eyes.