I had this thought a long time ago, but only recently revisited having downloaded Fable II due to Microsoft's fuck up.
 
So, some people say that "digital distribution is the future" but there are those (including myself) who tackle this issue with "I like to own the physical copy.  Something that I can hold and show".  Now, there has been copies of Blu-rays that have included DVD and/or digital copies, in the same box for the same price!  (such as: Iron Man 2 @ Amazon.co.uk).
 
Why can't games do this?  Games cost a LOT more than Blu-rays and DVD's combined, and this will satisfy both digital and physical gamers.  The thought of owning the physical copy and not needing to insert the game disc to play is awesome.
 
Sure, I could buy the PC version (if applicable) but I don't have a PC powerful enough to play games at their full potential (nor am I going to upgrade for games).  I'm NOT a PC gamer.
 
Then you have those who rent games and the used game market.  I don't rent games nor purchase used games.  i think this could be dealt with as the PC market.  In my experience, in the UK, when you try to return PC games (once opened), you cannot get a refund.  If you didn't already know, PC games require unique serial keys to install.  Obviously once it's used, the key is useless.  So the store wouldn't be able to sell the PC game again.  This could easily kill the used game market - unless game publishers release multiple versions of games (physical copy only, digital copy only, physical + digital copy).
 
Just a thought.