Barely comes bundled with Superdrive equipped machines either - you don't get a distribution disk (as you do, for example, with iPhoto), it just comes pre-installed on the drive. If you actually want to extract the application, you have to go through the whole procedure with copying all the .dmg files from the restore disks then mounting it with Disk Utility.
It's a real pain. I pulled out most of the stuff from the restore disk that I might want to add after a clean install and burned it to CD, to that when I upgrade to Jaguar (I plan to do a clean install rather than just an upgrade install) I can drop iDVD onto the machine with a minimum of messing around.