MGS4 will sell a lot of copies and will boost hardware temporarily, but that game coming out will not all of a sudden make the PS3 sell like the Wii. Right now PS3's only barrier is price. Think about how sales have been affected over the past year.
Over the summer there was a price cut(sort of) and it saw a temporary boost in sales but nothing lasting because people who would pay $500 for a PS3 already bought one of the 20gig models.
Then in the late fall PS3 went down to $400 and sales boosted again and haven't gone down since. This because a new group of people who wouldn't pay more than $400 for a gaming system were now buying the system.
Another event that has had a big effect is the end of the format war. Sales of the PS3 have definitely gone up because Blu-ray is the winner.
Can anyone think of a single game that have increased hardware sales for more than 2 or 3 weeks. It is no longer the case where there are no good games for the PS3. Now the only thing stopping consumers from buying a PS3 is its ridiculous price(and the awesome power of the Wii).



^Guy pissing on Microsoft Sign







