Choices, choices, choices. We've got three home console platforms: PS3, Xbox 360 and Wii. (Don't forget the PC!) And that's just current gen! The PS2 is still going strong. Add to that, portable platforms the PSP and the DS. Game developers do have a wide range of choices. Yet some choose to stick their games on a single platform. Not Okami producer and current Platinum Games exec Atsushi Inaba, who states:
While the level of what's missing has reduced, I still feel that none of the platforms totally satisfy my needs. That's why different games on different platforms is the way to approach the situation. Also, from a business point of view, it doesn't make sense to develop for a single platform at this point.
True, but don't count on third party exclusives to vanish anytime soon.