Analysts say it's inevitable: at some point in the industry's future, all games will be in digital format. Physical media will die. It might take some time, but we're already starting to see evidence of the shift, and developers and publishers are supporting it.
As usual, it always comes down to a question of money. Developers have been complaining throughout the generation that games have become too expensive to make, and taking risks is ill-advised. At the same time, gamers continue to complain about the supposed high cost of games (the fact that a SNES cartridge cost $60 nearly 20 years ago doesn't seem to matter to such complainers), and publishers have made it plain that digital delivery is simply more efficient.
So if both the manufacturer and consumer gets things done for a cheaper cost, isn't that a good thing? It's a no-brainer for the game makers, but will gamers who value their physical, tangible game collections opt for a digital copy of a game if it's cheaper ? How much cheaper would it have to be? Of course, if we don't even have the option between digital and physical, this isn't even a question, anymore. But we should have the option for quite a while, right? What would you choose?
In my experience, people talk big about what they want, but the instant you save 'em a few bucks, they change their tune. It's a little depressing, but that's how things work.