If you've looked around, you probably noticed a high-def DVD player, be it HD-DVD or Blu-Ray, is expensive. Expect to pay $500 or so unless you get one bundled with a game console where they are subsidized.
Now they won't follow this suggestion, but the reality is they didn't need to make the move to these new DVD formats. Regular old DVD can actually handle pretty decent HDTV movies. Not as good as the new formats, but a lot better than plain DVD. I've seen videos with the latest codecs that pack a quite nice HD picture into 2.5 to 3 gigabytes for an hour. I've even seen it in less, down to 1.5 gigabytes (actually less that SD DVDs) at 720p 24 fps, though you do notice some problems. But it's still way better than a standard DVD. Even so, a dual layer DVD can bring about 9 gb, and a double sided dual layer DVD gives you 18gb if you are willing to flip the disk over to get at special features or the 2nd half of a very long movie. Or of course just do 2-disk sets.
Now you might feel that the DVD industry would not want to make a new slew of regular DVD players with the fancier chips in them able to do these mp4 codecs when something clearly better is around the corner. And if they did do this, it would delay adoption of whatever high def DVD format they are backing in the format wars. But in fact, these disks could have been readily playable already, with no change, for the millions who watch DVDs on laptops and media center PCs. More than will have HD DVD or Blu-Ray for some time to come, even with the boost the Playstation 3 gives to Blu-Ray.