The PS3 return ? Exclusivities won't help ...

[Bodhesatva]

I'm just going to repeat this for emphasis. Let's go through your thought process:

1) Exclusive Game [X], Game [Y] and Game [Z] were not system sellers.
2) Therefore, no game is a system seller.

I would recommend that your sample size is too small and, much more damning to your hypothesis, we actually have recent, very conclusive examples of exclusive games selling systems. This proves that exclusive games can sell systems: it's just that Game [X], Game [Y], and Game [Z] are not among them.