Sony has already told us that the PlayStation 4 will lack a bundled camera to keep the price down. That's not the only reason though, as Sony CEO Andy House spoke with Business Spectator Australia stating that "the vast majority of the audience that we speak to tells us that their primary wish is for the full controller interface and there's not necessarily a huge emphasis being placed on camera interaction."
Originally Sony was trying to bundle PlayStation 4s with the camera while still targeting the $399 price point. The company would have lost too much money had this gone forward, and even now they're losing $60 on each PS4 sale. Andy also stated that they may bundle the camera with the console down the line to attract a wider audience.