Lets say, the Xbox one allows for games to be installed to the harddisk.
I would then go to the gamestore, buy or lend a few games, install them at home, return them and get me money back.
I get to keep the games on me Xbone and the store gets no money, nor does the developer get any money.
Come on, back in the 90's and very early 00's it was easy to circumvent copy protection for PC games.
It's the later half of the 10's today, you really think MS would be that stupid to allow people to install games without owning the retail disc?