^ This is actually happening to some degree in the video game world. With some older games that have key-based copy protection schemes (i.e. there's a printed serial key somewhere in the box together with the CD that you're asked to enter during installation or at the start of the game), publishers have made deals with distribution platforms like Steam that allow you to enter the key into Steam and have the game added to your Steam account, so you can install it digitally via Steam.
It's also being done for some new games right of the bat. If you buy a copy of CD Projekt's fantasy epic The Witcher 2
in a brick and mortar store it's usable as-is without an online connection, but you can go to GOG.com (the excellent, DRM-free online game retailer run by the same company) and register your game there, which provides you with a DRM-free digital "backup copy" you can download at any time.