The real issue I have with an all-digital future is the fact that companies come and go. Sure, Sony/Microsoft seem stable now, but who knows in 20 years? What will happen to our Playstation Network titles should those companies tank? I can play Sega Genesis games even though the company that designed the system has been a shell of its former self for over a decade. I'll be able to play my disc-based PS3 games in 2050 assuming I have a working console. Will that be true with these digital only titles? Will they be destined to be simply a memory of a game I played one time, without the ability to go back to it?
As someone whose entire gaming library is important to me, and who never buys games new, this worries me.