You're making a lot of assumptions about games. Sure, the Playstation and Playstation 2 have had some of the most diverse exclusives ever, but this may all change with the PS3. Companies like Konami and Square-Enix have stated that if sales of the PS3 aren't good enough, they may go multiplatform. The PS3 has a bad reputation in Japan, in particular.
Right now, the 360 is winning the games game. There is no way to dispute this. And for the next year or so, they will continue to do so. As long as the software is in Microsoft's court, by your reasoning, sales will be also. And because sales are so bad for the PS3, software development for exclusives will be slower.
Personally, I think the PS3 will probably surpass the 360 at some point due to the global popularity of the Playstation brand. But I may be vastly overestimating its popularity in Japan. This is mostly due to personal biases -- I just think Sony is better at executing in the game market than Microsoft is.







