The model has changed, however. Today, it's android & iphone that are driving the industry forward. These are platforms that don't coordinate as tightly with carriers.
Frankly, RIM's problem is that their leadership is stuck in the old model. There was a generation of senior executives in the mobile industry who truly knew better than the nerds: Regardless of your passion for development & openness, it was the carriers who make or break you. RIM's risk now is to replace one extreme attitude with another extreme (too open, too independent) and then completely self-destruct.
IMO, the key to success is not anything listed in this letter. They need to reboot their leadership structure with folks who understand that a good relationship with carriers is critical, but you don't cling to them for survival. Android & iPhone are vulnerable in this space. They're spending too much time giving carriers the finger.
IMO, the only company that really has a shot at relevance is Microsoft: They're still playing nice with carriers & they have an incredibly easy development environment, but they're also exploring territory that hasn't been authorized by the carriers.
In the sense that they're 'failing', they're failing because they're not nurturing the development ecosystem with funding. If Microsoft set aside 50 million dollars or so for investing in INTERESTING mobile application developers, they could solve their appstore app quality problem and really make a move on the industry. Microsoft should take advantage of the fact that the carriers aren't thrilled with Apple or Google. They're really well positioned to strike, if they can just get the app quality problem solved.