The way I read what he is saying is. He has already played Xbox games, so BC (on an Xbox360) doesn't matter to him. He has not played Gamecube or PS2 games so, in a sense, if he gets a Wii or a PS3, he will be getting multiple new (to him) consoles instead of a single new one (to him).
If he bought an Xbox 360 his money goes to only an Xbox360 (he doesn't need it's BC).
If he bought a Wii his money goes to a Wii, Gamecube, N64, Super Nintendo, and Nintendo.
If he bought a PS3 his money goes to a PS3, PS2 and a PS.