Judge the offspring by the parent....whatever the PS2 did, the PS3 needs to do similar. Anything lower is a market share loss. So if the PS2 held 70% marketshare, that's what the PS3 will need to do.
Ofcourse its a makret share loss but is it realistic to expect that a console franchise will always do as well and even do better?
So lets say that Sony falls to 50 marketshare would that mean fail?
I kind of doubt it though they will reach 50%. I expect less, but lets say 50% just for the sake of discussion