Believe it or not, there are people that will wait for the 80Gb since it is the same price.... Not all decreases in sales should be due to shortages.
That's why in Europe the PS3 is readily in stock but it declined in sales....
PSN ID: T_Gears
End of 2009 ltd sales:
Wii = 67-68m
X360 = 38-39m
PS3 = 34-35m
Prediction: The PS3 will surpass the 360 on weekly sales after it drops to $299 on all regular weeks (no big releases).