"The problem is that these less violent games play a very important role in the PS3's library;"
This would only be true if there were "violent" exclusives that are available on the 360 but not on the PS3. Next year the PS3 has Killzone the 360 Fable2 as big exclusives. Therefore I think your analysis is flawed.
Besides Ratchet and Uncharted will most likely reach their million copies sold so they are successful enough.







