Sounds like just another reason for the move in general.
Over the course of the gen, it would save a huge amount of money, but it's likely not the singular reason.
Remember that their drm gives them a huge amount of control over many sectors.
It pushes their proprietary software azure on used game retailers, gives them a cut of every used game sale, and controls market prices to some extent. It also incentivizes switching to digital distibution where overhead is lower and prices will remain the same.
Plus it has functional benefits.
Faster access times over bluray
Allows for the system to run programs without a disc making switching to other content faster
Monetizes hard drive sizes in terms of console value perception(One year in, no price drop, but disc size increase)
From a business standpoint, it's very smart.
The only negative is that it absoutely shits all over the traditional core gamer, but it's also unlikely that the traditional core gamer is the same as their new target core audience.
