The costs is the biggest part of BS Sony can think off. The whole Emotion Chip is nothing more than a budget chip now and doesn't make the cost on a PS3. It has more to do with the fact that companies don't like it when people sell their PS2 for a PS3 when the PS2 is still in production.
It has been nothing more than a smart sales talk. Sony mentions it will have BC then sell them for a few months then silently introduce a lighter model without all that stuff.