This console/format generation isn't called a war for nothing. Sony is trying to get serious about winning this generation by radically refining their business model prior to the holiday season so they can gain market share.Originally Posted by Spartan–117
My guess is that they have finally realized how much money there is to be made from digital content distribution (even on weaksauce PSN) and want to capitalize on that by offering a new model for the lazy/scared people who are afraid to install their own larger hard drive.
Furthermore it's not like the new model will actually cost Sony more money to manufacture as the larger capacity hard drives will probably be cheaper for Sony to buy in bulk since they're more common, and Motorstorm is a first party game that has sold well and has basically paid for itself.
Also, don't underestimate the power of economies of scale. The more PS3s Sony makes, the more their costs go down.