Though early signs point to Killzone 2 being a massive success in retail, they also indicate a very small hardware bump as well.  That means that the majority of people that wanted Killzone 2 already owned a PS3, unlike when Metal Gear Solid 4 hit retail a half a year.

OTX analyst Nick Williams spoke about the the PS3's low sales in a recent interview.  As other analysts have predicted, he indicated that the PS3 was in store for a price cut this year, and that sales have been hindered up until this point as a result of the price.

Interestingly though, he slated God of War III as a 'pivotal' release for the PS3.  Williams explains "According to our latest consumer tracking study, only two in three people who plan to purchase God of War III currently own a PS3".  That means that God of War III may just end up being the system seller that Sony has been looking for.  Williams quickly added, though, that this is contingent on the PS3 being within ballpark price range of the Wii and the XBox 360.