The main and foremost reason the MicroSoft uses the "DD is the future" propaganda is because MicroSoft wants it to be the future.
So they can control more and prevent customers from reselling their games, movies and music.
But what they totally ignore is the fact that far from everybody have a fast connection like Cable or DSL and customer like the convenience of the physical media of a widely supported format.
If electronics break ( *cough rrod cough * ), they only have to replace the electronics, not the media.
And if the format is widely supported they have more than enough choice about where to buy the new electronics, which brand and with which features and options.
Even if the amount of Hi-Def DD-consumers would start groing, then the ISP's want their peace of the pie too and consumers will have to pay more to consume those Digital Downloads.
Microsoft can hope whatever they want, it'll take much more years than they hope before those Hi-Def Digital Downloads means anything.
And even if the time arrives, a good video-game will take up at least 4 till 5 times more storage-space then the latest games.