Has the OP actually counted the number of exclusives Sony's World Wide Studios has made for the ps3? I'll give you a hint, it's A LOT more games then Nintendo made for the Wii. Claiming it's okay for the Wii because "Nintendo makes more games" is laughable.
As for it, I have said it before on here and apparently it needs to be said again. If not for Sony/Nintendo/MS developing the games as EXCLUSIVES most of them would not exist at all. If every game was going to be on every platform Sony, MS and Nintendo wouldn't even bother funding the majority of games and would just throw that money at marketing their systems and 3rd party games. Why? Because that is what that money is for, selling their consoles not developing some multiplatform game that sells well.