Did Sony Profit from the Walmart $100 Discount?

[bumidan]

Also, does Sony profit from the MGS4 bundle? 

Just a question.  If we assume that retailers make a small profit (less than $50?) on actual consoles (as was pointed out in some previous thread) THEN why would Walmart allow a $100 discount?

Does this mean, that Sony had some incentive for Walmart to discount their PS3 systems?

 Also, for bundles, if Sony had to buy MGS4 from Konami (to guarantee some sales), do they profit from the bundle?

If you have some numbers, please enlighten me.  Thanks.