Umm, I don't know where these claims of Killzone moving 70-80k PS3 consoles are coming from. Let's look at this by region:
Week of February 21 (the week before Killzone launch)
Others: 84k
America: 55k
(Japan: 16k)
Others + America Total = 139k
Week of February 28 (Killzone launch week)
Others: 103k
America: 66k
(Japan: 36k)
Others + America Total = 169k
Week of March 7 (current week)
Others: 84k
We seem to be exactly back where we were two weeks ago, with no discernible change in Others sales. Of course it's possible we'll see something this week in America, but that remains to be decided. Obviously we leave Japan out of this, because Killzone has not been released in Japan as yet, and trying to credit the Yakuza boost to Killzone would be inappropriate. So the number of hardware units moved by Killzone over the previous weekly average easily works out to:
169k - 139k = 30k PS3s (one week boost of 20%)
I leave it up to the individual posters to react to that as they may. 
PS Errr, the PS3 absolutely received a European price cut in November 2007. Go look it up if you don't believe me. And if you're going to play the "PS3 has only had one price cut!" card, you might want to mention that a $500 PS3 at launch had a lot more features included in it (most notably PS2 backwards compatibility) than the current $500 PS3 does.