That DualDisk shit is incredible. I'd just wonder about what the prices are.
And you're right about people buying more albums. I really believe that if people could see top performers like U.A. do their thing on DVD, and realize this isn't some skating-rink performance with a flat floor and a dead crowd, but rather an actual stage, a lively crowd and pro-quality mic/sound, then they would start supporting in larger numbers.
The people need to realize that this stuff is not a game, and they won't realize that until they start going to the shows. CDs can't do that alone.