that is true. I'm just saying, you can't take 40k xbox sales and 60k ps3 sales and say that's 40k lost sales. Who knows what it is. maybe it is only 20k lost sales.
i.e. 80k people would purchase BB on PS3, but if it's the xbox only 60k do so, cannibalizing the ps3 sales.
Ultimately, this is just something hella simple which everyone already knows which I have just muddied up. oh well.
http://en.wikipedia.org/wiki/Cannibalization_%28marketing%29