@Werekitten - I don't subscribe to the PS3 being at any risk anymore as it's more than sold enough to be sustainable now, but you must have seen some shrinkage of it's self shelf space in the last 6 months or so surely?
I think this is the crux of what many people are basing their thoughts on is that already retailers have started to act against the PS3 by no longer giving it the blockbuster marketing space it once owned. In my local game stores it's now even on shelf space for 360 and Wii and the PS3 is half to two thirds of them.







