Who said the PS3 was doing terribly when compared to PS2, and that it followed the GC/Xbox trendline?
VGC says differently:
http://vgchartz.com/hwlaunch.php?cons1=PS2®1=All&cons2=PS3®2=All&cons3=X360®3=------&weeks=156
Matter of fact, it's following EXACTLY the same as the PS2 almost