According to Reuters and its interview with Konami's North American and European operations head Kazumi Kitaue, the greatest PlayStation title might not be so Playstation oriented in the future.
Kitaue thinks that Sony can't win back user support with a $100 price cut, in his words, "I don't expect a substantial impact...With $500, you can buy a personal computer." In addition to that he mentioned that Konami would probably have to go with non-Sony systems so it can get its development money back.
Metal Gear Solid is a Playstation child, it would be odd to see and play it on XBox360 or PC, but people and time change. Kitaue also added "Since Metal Gear Solid was born for the PlayStation, we would like to keep it a PlayStation game, but we might have to take some steps."