I actually have a strong desire NOT to own physical media.
Anyway, digital downloads is not just about HD movie purchases. It's also about rentals of SD/HD movies, purchases/rentals of TV shows, concerts, music videos and more. People will get what's fitting for their situation and their wallet.
"Apple already sells movies, TV shows — and music, of course — on iTunes. The company has sold 7 million movies and 125 million TV shows on iTunes, Jobs said."
http://www.statesman.com/business/content/business/stories/technology/01/16/0116apple.html